I've only watched the first vid so far, but I have a few things to say.
You do a lot of desynchs that don't really help you. Especially against a character like Fox, you can get punished really badly for doing something like a close range ice block desynch. You also put yourself in a few bad positions that can easily be avoided by doing things like random offensive belays and using squall hammer to escape (which is fine against a lot of characters, but is pretty risky against Fox, especially on a small level like Yoshi's Story. I actually do this a lot too, lol).
You usually have better options than dthrow against fastfallers when Nana isn't close enough to do anything useful. Uthrow in particular works really well against a lot of people.
You should consider implementing wavelanding onto platforms into your game. A lot of people will shield when they're on a platform and you're below them, and you can just waveland next to them and start a CG.
Your use of squall hammer as an offensive move is amusing, but you usually have better options since squall hammer doesn't really lead to anything, whereas most other methods of stopping Fox's approach can lead into some sort of combo or grab.
Your edgeguarding needs work. You do a lot of flashy desynchs when Fox is off the stage, but it looks like they fail most of the time. Consider doing something more straightforward.
