K here is my critique
At 1:04 on the last vid you glided in. This was a risky move in the first place because you glided in against Marth, from above. Marth has ridiculous damage concentration (ie. most of his moves can do top damage above of him) above him, which means you shouldn't try that. Though it worked, and you got over him, so i suppose it was alright. The problem here being that you barrel rolled a bit to soon. This caused you to be in landing lag, and get smashed pretty hard. If you barrel rolled right before you hit the ground, so your in the rolling animation right when you hit the ground, you receive ZERO lag. Just something to keep in mind.
Also, I applaud your grab game, as not enough people use Charizard's under-estimated grab range to their advantage. A note though, Charizard's up-throw is his most damaging one, and you never used it once. I understood on some of the situations, a back or forward throw was used to toss him off the stage, and you got to take a chance at edge-guarding. This was good strategy, but sometimes you should throw the up-throw in there for the damage, especially early on in the match, when they have low %.
Speaking of edge guarding, you were pretty good at it, but you should mix it up a bit more. I liked how you spaced yourself, and used flamethrower, thats a good strategy, but try just using a standing rock smash here and there. Use it when they haven't grabbed the ledge yet, but are about to. The shrapnel from the rock can be a nice little surprise fro them.
In general, you abused his f-smash a lot in the last match against Marth. This is bad for 2 reasons. 1. Your using the same move a lot, and with a move with that much duration, its not a good idea. 2. The distance your at to use that move effectively is Marth golden zone. He is faster than you, and your right where the tip lands. Also watch out for over using move in general, like flame thrower, against who you were facing, thats fine, but against an opponent thats maybe a bit quicker, and a bit better at the game, you would get punished.
All in all you were doing good, and i was often surprised how quickly your opponents damage got up. Just work on the things I talked about here, and obviously get better with the other two characters. You don't need me telling you that though.