First of all Swei, I wanna say you've gotten a lot better and are clearly listening to the advice you've been given. So props!
Moving on to Olimar--you definitely need more basic understanding of the MU. Here's some biggies that stuck out to me:
-NEVER run up to Olimar and dash grab him from a long distance. You're asking to get spotdodged>grabbed or upsmashed. This goes for any character in Brawl. Pivot grabbing works nice instead, or charged upsmash if you can bait/predict the spotdodge, which is the usual reaction to someone running right up to you.
-When Olimar is in the air above you, stay directly beneath him and DO NOT JUMP. Olimar will either dair (if he's higher up), nair (if he's falling close to the ground--this will chain into upsmash typically), airdodge, or Whistle. Be patient and bait Olimar, then punish with upsmash, dsmash, Klaw, or pivot grab. Jumping up to meet Olimar is asking to get punished and you'll lose all your momentum.
-You're still using ftilt too much. You have a bad habit of covering empty Klaw Hops with it, which is honestly just a rookie habit. My advice: Play a ton of matches without using ftilt at ALL. It forces you to be more creative with your approaches, and you'll soon learn when's the best time to use ftilt. It's more of a bait move than a reflex, which is what it is for you as of now. If it helps, have a friend punch you every time you ftilt. I'm dead serious. I used to have a nasty spotdodge reflex, and my friend hit me every time I did it. I became more aware of it, and now I only spotdodge when it feels right, not because it's a reflexive habit.
-You're too aerial against Olimar. I know the initial reaction to having Pikmin thrown at you is to be on the air, but the Pikmin will still latch onto you, and then you're in the air to be jiggled or killed. Olimar's really good on the ground, but Jab literally beats all his Pikmin attacks if you time it right. Jab is a nightmare for Olimar, especially with jab canceling thrown in.
-I'm not sure if this was intentional or not, but good job getting that fsmash KO game 3 by using the purple Pikmin as an extended hitbox. Olimars typically throw purples at you when they're offstage so that they can knock you away from the ledge--if you can time an attack right, the Pikmin can extend your attack, almost always gimping Olimar in the process. This only works on purples since the rest latch onto you.
-Good job picking up on your opponent's weakness to jab>regrab. You'll find some opponents are more vulnerable to certain GR mixups than others. If you spot a possible habit to being GR'd, exploit it. Some people actually think jab>regrab is a true CG and don't realize they can spotdodge or attack.
-Throw in some Firebreath every now and then. It's got more range when fully charged than Olimar's pivot grab.
-Speaking of, try using pivot grabs more to punish landings. It helps.
-Be careful fsmashing Olimars on the ledge--it's a surefire way to get fair'd. However if you notice the Olimar likes to instant return, fsmash will beat him every single time. You'll find a lot of top Olimars like to use this since they typically can get off an attack quickly plus it looks fancy. I've fsmashed literally every top Olimar out of instant return multiple times.
Overall like I said, you've improved a lot, Swei. I know you'll get even better next time.
Kalm, I overlooked your videos. Will critique them next soon as I have time.