I'm gonna give you guys a couple of tips on how to play the matchup.
1. There's this one special technique where you if you don't want to play a certain matchup (Most don't prefer Squirtle) you can just SD yourself so PT can't switch between characters when you're getting knocked off. Warning: You should only do this at high percents & you should do it immediately when a Pokemon is dying, not when they are on their next stock.
2. Charizard, you got a lot of combos you can do. We can chaingrab and bair him like a lot of ther characters. We can down throw to down tilt him on ground and edge. We can do this down throw to dash cancelled down smash (Where you cancel a dash by turning the other direction during the frames where you can dash dance). We got our famous buffered pivot infinite along with Dash Dance Pivot Grab on edges and upward/downward slopes. We can also do this down throw to a walk into a jab as a combo. Also we have d throw to f tilt. We also have the wall infinites along with this Halberd dash dance pivot grab and stand grab lock on the edges of the second part of Halberd.
3. For the stage selections, I would pick Halberd (For most of the stuff I mentioned (Also, Ivy can get regrabbed once with dash dance pivot grab where Charizard has his lock on Halberd)), Yoshi's (Charizard slope infinites along with us recovering better without getting punished as hard), Smashville if you are fighting Squirtle a lot, Frigate (Charizard slope infinites
), Rainbow which you guys probably know why, and Brinstar (For less ground game for less Squirtle ground abuse, everyone having poor recovery, D3 being an aerial beast, and Charizard slope infinites).