GANONDORF
This match is very difficult if the Ganon player spaces his forward and back airs well to shield pressure you and never does any "unnecessary" approaches that leave him open for you to move into him. He hits hard, he punishes hard, so this match really requires the Mewtwo player to be spot on in timing attacks, but fortunately Ganon has an easy to gimp recovery and can be comboed pretty well. This makes Ganon one of Mewtwo's **** or get ***** match-ups and you may start to treat Ganon's play style like a Marth that can't invade your space as easily, but can easily just pound it into the ground. Finding a rhythm is key.
OFFENSE: Your approach is usually going to involve slipping in down tilts following shadow balls and well timed grabs often following poorly spaced aerials or poor positioning. Your kills will come more from edge guards than up throws, so keep that in mind. I don’t remember Ganon’s magic number, but it is around 140% or so. Neutral air is always a good move to use between aerials, and well timed Confusions might help out in getting through Ganon’s F-airs. He’ll often try to keep you out by using jabs following his aerials, so keep that in mind as you approach and you might get him to bite, then get guarantee your opener.
DEFENSE: Keep moving, be careful when you push into him to get into your range for landing down tilts and grabs, try not to whiff or you will get punished. Watch for empty short hops to grabs, since they are practically guaranteed back/forward airs on you. If you’re forced to shield F-airs it will destroy your shield and then your head will be vulnerable. Ganon has good range but poor horizontal movement speed so try to escape to a ledge or across the stage and let your shield recharge until you can try to get inside him again. Be wary of his Down B. If you see it coming, you can Disable it, grab him out of it or even side step and still have time to punish most of the time.
Final Thoughts: Shadow balls are good since it also can force Ganon to eventually start making moves toward you. Ganon is a good character to get a rhythm on, but can easily take it away with one good aerial. Once you can read him, you’re in good shape. The more times you set him up off of the stage, the better. Go out and get him with back airs when he’s off the stage, especially during his Down B. You can just ledge hog him from there when he’s forced to up B, you can down smash and follow up with back airs, or just go get him with back airs until he can’t recover anymore.
SHEIK
Sheik is a very mean fight, contrary to popular belief. A lot of the things you do just get out prioritized by Sheik. Sheik has better grab range, has low attacks, can crouch cancel your combo starter then combo you back, much harder to grab than Marth, and much harder to KO than Marth. The things you have going for you in this match are less gimp KOs from Sheik, good combos when you can start them, and decent edge guarding pressure.
OFFENSE: Usually at lower percentages you want to start with more down throws since they have to DI away or they get comboed into down tilt and another down throw. Since you know they will DI away, depending on where you grab them on the stage, you can build most of your damage early from there by tech chasing. The key here is to figure out if they’re someone that likes to move away and try to cross you up or someone that just wants to get away and stay away. Once you figure this out you can down throw and even teleport tech chase, or you down throw and wavedash forward once and look to pivot. The second option will give you more success because even if you guessed wrong, you’re still in position to pressure the Sheik by dash dancing towards them after a tech.
Shadow balls get canceled by needles, but you usually can use them to cover your approach as they needle spam, and you can sometimes get them to throw needles at the apex of their jump instead of as they’re landing which can be an opener if you’re ready for it. Getting them to do that opens up teleports underneath them, and wave dash down tilts as they’re throwing needles, setting up for combos/grabs.
DEFENSE: Sheik aerials are just better than yours, so usually all the aerials you’ll land will either be from a whiffed attack or when Sheik can’t do anything about it. You can punish poorly spaced down smashes with a Forward air out of shield. You can stop Sheik’s low dash attacks with confusion*, (Experimental strat) crouch cancels, or a baby wavedash back to shield for a possible shield grab. Use Sheik’s standing needles as opportunities to close the distance by teleporting through them or max ranging them and charging your shadow ball. Do your best to avoid grabs, especially around 120-130% since that is Sheik’s kill range on Mewtwo. I’d DI away from down throw > forward air at 140%+ and hope the Sheik doesn’t know how far you’ll go. More often, you want to try to eat the Forward air instead of the up air, so DI away and DI up for the forward air and hope for the best.
Don’t let Sheik into your space easily, wall off her dash dance with down tilts and shadow ball, escape from jabs on your shield as they often lead to grab attempts, encourage forward tilts since they can be difficult to space on Mewtwo and can lead to your own down tilts, grabs, and shield grabs.
EDGE GUARDING: Edge guarding Sheik is usually pretty straight forward, but it is hard to get gimps. Most of the time you’re just camping the ledge until she up Bs then forcing her to have a laggy landing on the stage, back throw, and repeat until you can’t anymore.
Last thoughts: Sheik’s magic number on FD is 128%, though you’ll usually have to go higher just because Sheik can easily deny you your grabs if you force them. A lot of the time you just have to go with the flow and keep waiting until you get your kill opportunity. You’ll probably see a lot of down tilt > forward air KOs since they’ll be afraid of that grab.