Oh man, I missed quite a few discussions again.
I'll add my two cents to all the match-ups I have a bit experience against.
One thing that you should always keep in mind when playing vs Toon Link is definitely the fact that bombs bounce of the shield and there still are a threat in the air. So shielding and moving backwards is especially important vs Tink's bomb throws to avoid situations where a bomb may surprisingly hit you afterwards. Purple Side B is so important in the MU as the side b beats the boomerang and arrows and keeps an active hitbox which means it's a good tool to punish boomerangs. (and arrows too) Avoiding the bombs is in my opinion a key-element, because by avoiding the bombs you don't give Tink the possibility to follow up the bomb with an aerial. Depending on the range, fsmash can be useful vs boomerang and arrows too, but I prefer purple side b. Offstage I sometimes throw a purple to catch Tink, but this only makes sense when he didn't take a bomb out first. Otherwise you'll just waste your purple while Tink still comes back which would be a bad trade after all
Also in this MU, powershielding will be important. Any other side b than purple can stop arrows and the boomerang when timed right. Also be aware of Tink's strong bthrow. Especially with rage, you should not let yourself get catched by a grab near the ledge.
Tink's zair is a good tool to keep pikmin away. So when you're throwing Pikmin at him, he can stop them with his zair if timed right.
I'm pretty sure that Olimar's fsmash beats Bowser Jr's side b. So a main approach tool of Bowser Jr doesn't really work on Olimar. Fsmash can even be fast enough to destroy a mechakoopa first and then perform another fsmash to hit Bowser Jr. as far as I can recall it. Getting pikmin attached on Bowser Jr isn't that hard. Of course fair can eventually pretend pikmin from attaching on Bowser Jr, but the fair has also some cooldown, therefore double side b should at least get one pikmin attached on him.
There is one thing I'm not sure about. I'll probably test it tomorrow to be sure about. I wonder if the fsmash keeps an active hitbox after destroying the mechakoopa or if the hitbox disappears after the destruction of the mechakoopa. This is an important thing because an active hitbox would give Olimar an important advantage similar to Villager's lloid setups. As said I'm not sure about this and I'll just test it.
Bowser Jr's Side B fakeouts should be punishable with a side b and even if it misses, you're not letting yourself open for too much, because Bowser Jr's Down B takes some time to take out a mechakoopa and the mechakoopa keeps some time to approach you too. Also Side B has some startup frames, so trying to punish the fakeouts on reaction shouldn't be a bad idea after all no matter if the bowser jr goes for down b or side b afterwards. Even if he shields, well the pikmin toss at worst would miss while still not creating any opening for the opponent.
What may work in Bowser Jr's favor is the rage effect as he can survive pretty long vs Olimar. This makes his killoptions like smash attacks and upb to hammer really scary. However in the footsies game I am normally out of the range of any smash attack.
As my brother is a Lucas main, I can tell some things about this MU. First things first, a yellow pikmin attached onto Lucas is pretty good as most of his moves have electro-hitboxes. Only his fsmash, upair, jab, dtilt and zair can be used to actually kill the yellow pikmin. It's good to know because this means his get off options are very limited vs yellow pikmins. In general I prefer throwing out many side bs to wrack up damage as this works best so far. Keeping the distance while attaching pikmin on him. Also going offstage vs Lucas is generally spoken a bad idea as he has this electro-hitbox during his upb making it hard to land the spike(I only catched him a few times with purple dair but timing looks very strict). Often you get hit instead of getting any further advantage by going offstage. Therefore you should better just try to cover ledge getups instead. Dtilt near the ledge can be nice to catch lucas during his upb and maybe get the 2frames punish. You can throw pikmin at lucas with your side b to shorten the recovery, but most of the time, the effect wasn't that big vs lucas and he still managed to grab the ledge anyways. You can stop the PK fire with your side b, but keep in mind that the pk fire hitbox gets extended by the pikmins.
Lucas can also reflect Olimar's smash attacks with his fsmash, so better be careful when to use smashes vs Lucas.
Another thing I found pretty useful is juggling Lucas. When positioning yourself under Lucas, his best tool is to dair, but when you jump and bait out the dair, then fastfall you can catch him afterwards with an upair. This is interesting, because of his limited options to cover his landing. He has to expect you to either go immediately for an upair and throw out a dair higher up in the air or he expects you to first only go for a bait and then upair him and time his dair closer to the ground. However this works best on fd and smashville which are two stages I honestly don't pick often vs Lucas. I prefer playing vs Lucas on stages with more platforms such as Battlefield, T&C, Lylat and Dreamland. In general I like playing as Olimar vs Lucas.
Charizard is interesting, because as an heavyweight he survives pretty long and therefore can benefit of rage. His upthrow is buffed by any stage with higher platforms. It's the main reason I would play on stages like FD, Smashville and maybe Lylat. Also Charizard's jab looks pretty fast. A friend of mine likes to space with nairs in neutral and cover his landings right afterwards with a jab. Also the fire of Charizard can be pretty annoying as it can make it harder to attach pikmin on him and the fire is also pretty good to cover ledge getups or at least corner you right away. Also keep in mind that Charizard has some moves with super armor that he may like to use. Edgeguarding Charizard isn't that easy too. I honestly prefer to cover ledge getups instead of going offstage vs Charizard. I like juggling Charizard above the stage. His dair isn't that fast and therefore it is doable to land an upair before his dair hitbox becomes active. However keep in mind that he could go sometimes for a down b instead and catch you when performing an upair thanks to the super armor. What makes the Match-up a bit hard is the fact that Charizard has much killpower and this gets even buffed with rage. Charizard as an heavyweight will benefit much of rage vs Olimar while Olimar has to build up much damage and the higher the percentage, the more you have to work for the percentage as combos won't work anymore at higher percentages.
I feel like Olimar slightly wins the match-up, because he doesn't have to approach Ganondorf after all. He can stay out of Ganondorf's range and ignore baits such as throwing out many upsmashes in a row i.e. The neutral goes to Olimar by far. However if Ganondorf ever lands a side b and Olimar misses the tech, for some reason Ganondorf's down-smash can connect before Olimar can act from the ground. At least this worked a few patches ago. I haven't played many Ganondorf players since then and if so, they didn't use the dsmash after Ganondorf's side b, so I can't say for sure if it's still the same. Especially after the whole changes on getup frames of many characters, this may need some testing again. If it still works, Ganondorf has a quite strong killsetup vs Olimar. Also offstage Ganondorf can be very scary with his dair-spike, upair and bair. So you have to be very careful when recovering vs Ganondorf. Probably the best thing would be to use the upb without any pikmin to recover high and far away from Ganondorf maybe even on a higher platform in order to have the time to plug pikmin right after landing onstage. When you get Ganondorf offstage and you have a purple pikmin, throwing the purple at ganon while he tries to recover will most likely be enough to gimp him.
I also know that Olimar can crouch under some moves of Ganondorf. I know that he can crouch under Ganondorf's down B. I think he can also crouch under the normal-angle fsmash of Ganondorf. Also while it's not really that useful, he can crouch close to Ganondorf when he is performing the Warlock Punch and the punch will miss Olimar. However as said, the warlock punch isn't something you'll have to face often and most of the time you'll probably go for an immediate punish during the startup lag of the Warlock Punch instead of waiting in a crouch close to Ganondorf.
The main issues in the match-up are rage(as Ganondorf benefits much of this when you don't gimp him) and being offstage vs Ganondorf is probably a situation you don't want to be in. However as Olimar wins the neutral and doesn't have to get into the range of any of Ganondorf's moves, he can safely wrack up percentage and then finish the stock sooner or later. This is the reason why I would put the MU slightly in Olimar's favor.
With the 1.1.3. patch, Bowser got some significant buffs, especially buffs for his grabcombogame. With 1.1.4. the koo-pa doesn't work that long anymore, but still his combogame is pretty good out of grabs. Most of the time, Olimar will have to stay out of Bowser's range and at some points get a grab in order to wrack more percentage with dthrow + upairs. Offstage I think Bowser isn't that scary. He can't jump too low offstage, he has no spike options, his bair is pretty slow, his nair isn't really good offstage, so all what's left is his fair offstage or performing his fire near the ledge. Keep in mind that Bowser can get kills on platforms too with his side B command grab. So I would like to pick flat stages such as Omega or Smashville at best. Rating the match-up as even seems not far off especially because Bowser as most heavyweights gets scary with rage. However Olimar has a good neutral vs Bowser and he can wrack up percentage vs Bowser pretty effective too. Bowser has problems getting something started vs Olimar, but his killconfirm, especially with rage, is something you always have to keep in mind as well as a rage side b on a platform which can also be a strong killoption. I would guess it's even or slightly in Olimar's favor because of the neutral game advantage.
Mewtwo can be very annoying with his side b. You have to be careful when to use smashes in order to not die early. Also Mewtwo has a killthrow and he has strong smashes which can lead into some early stock losses too. It's hard to juggle Mewtwo as an Olimar player because his nair can beat our upair(as well as fair, dair, bair). That's all I can think of right away.
Respect Falco's reflector. As it has a hitbox that is thrown away, I often find myself approaching with dash shield. When you shield the down b, it usually has enough ending lag so you can get a grab punish right afterwards. Also in neutral you should probably only use side bs. Pivot fsmashes are risky because of the reflector especially because it covers a good range after all. I like to dtilt to punish aerial approaches of Falco. Falco can be a threat offstage because of his fair killing pretty good offstage. Also his bair is pretty fast, so he can punish you pretty good with either a bair or fair when recovering too low. Olimar isn't that bad to wrack up percentage at low% easily, especially as Falco has no combobreaker. I often find myself conditioning Falco to reflect Olimar's side bs and then go in with dash shield afterwards to get a grabpunish when he still tries to use his reflector at closer range. From what I experienced so far, Falco isn't that good at approaching. However he has some low% combos.
From my experience Olimar has a bit trouble to really get things going. If he however gets a grab, he can get quite some percentage onto Falco. Also Olimar has a hard time recovering vs Falco. And you have to be very careful when to use an fsmash. These are in my opinion the big issues Olimar has in this match-up. However he definitely can condition Falco into reflecting side bs in order to later on get a grab and wrack up some percentage.
I would see the Falco match-up at least slightly in Falco's favor mainly because of his strong offstage game giving Olimar a hard time to recover.
I've played a few Samus players so far and while you have to put in some work, I feel like Olimar wins the match-up. You can destroy Samus' missiles with the fsmash and Pikmin on the way back to Olimar can block a fully charged charge beam of Samus too. This is the main reason why I tend to always have at least one pikmin on the way back to keep me safe from a fully charged charge beam. However keep in mind that half-charged beams may fly over the pikmin and therefore still be needed to be blocked. Her zair and her grab have a good range from what I remember. I like to pick stages with platforms such as Lylat, Battlefield, Dreamland and so on because you can better avoid projectiles with some platforms to jump around. Especially as Samus can't follow fast in the air, you don't risk too much by sometimes jumping on a platform. Also Samus can get comboed pretty well by Olimar once you get a grab. Egeguarding Samus isn't that easy however, so I honestly prefer to just cover ledge getups instead. What may make the match-up hard sometimes for Olimar is the shieldpressure Samus can apply when a missile hits your shield(if you don't get the powershield on it) or you once need to shield a charged beam. These are the main tools to slightly decrease your shield and make you perhaps vulnerable for a dash attack even when sitting in shield. Also the projectiles may condition you into shielding much which allows Samus to get a grab. However I can't remember Samus getting much out of grabs. Olimar and Samus both have to put in quite some work in neutral, but Olimar can get more damage out of a single opening. Therefore I would tend to say it's in Olimar's favor.
Cloud has a good tool to force Olimar to approach, because Cloud in neutral often starts with charging his limit and normally people don't want Cloud to fill up his limit for free. So Olimar needs to do something. He can of course throw pikmin with his side b at Cloud to get him into shielding and therefore stopping his limit charge. Also pikmin toss is good to block Cloud's projectile. It may even allow you to punish him right after the pikmin blocked the projectile. Also Olimar has a good tool to punish Cloud performing a dair when in the air trying to land. The pivot grab is amazing for punishing these dairs as well as pivot fsmashes. However offstage Cloud can be dangerous as he has two spikes he can go for, he can throw out his projectile(with limit, his projectile can even mean an early death for Olimar offstage). On the other side, Olimar can also punish Cloud for his upb when he doesn't sweetspot the ledge with something like Down-smash. As Cloud has not the best options out of grabs, shield is a strong option vs Cloud besides blocking his only projectile with pikmin toss. Also as always, be aware of extended hitboxes thanks to attached pikmins on your enemy. Don't get hit by the multihit-fsmash because of extended hitboxes.
Honestly as for now I feel like this match-up is even. Both characters have the tools to gimp the other. Both characters can force their opponent to approach. Cloud is good at juggling and your best bet to get out of the juggles is a well-timed whistle. I don't really see one or the other having a real advantage.