Okay, here you go--
Squirtle does pretty well for himself. Falco has to be very careful in a lot of situations. Jab can stuff Squirtle when he's up close, but Squirtle's F-Tilt outranges it, and Squirtle's Jab is faster. Both moves are faster than Falco's grab, and Squirtle's grab has greater range. When you jab, don't rapid A. Always grab before that point--Otherwise, you'll get SDI'd into an aerial of choice.
When Squirtle grabs Falco, he gets a U-Throw, which usually puts Falco in a terrible position, due to Squirtle's short-hop U-Air being so great at frame traps and a Hydrograb being able to trap the ground he falls on with little risk. A well-timed Squirtle U-Air beats Falco's D-Air, too. Falco must take great care not to be put above Squirtle.
Squirtle can have difficulties getting back on the ground against Falco. Keeping Squirtle off the ground is important for Falco. Falco's Jab is difficult to get around, for fear of his grab stuff. Feel free to camp; it will be easier if Squirtle can't KO you until ~160%. I'd say it's about even.
Ivysaur gets molested. Can't do anything about Falco's camping or his close range game. She is edgeguarded by Falco pretty easily. Falco is light enough to make DI'ing the initial hit of Bullet Seed pretty easy. The only dodge that Falco should be doing is his super-distanced back roll--If you keep coming at Ivysaur with quick attacks, she can't do anything, but spotdodging and airdodging will allow her to get a grab or strong hit here and there. Juggle her with Dash Attack. Spike her into the ground again and again. Watch out for Ivysaur's Dash Attack, though--It's Frame 4, clanks with most moves, and hits fairly hard.
The matchup is really bad for Ivysaur--25-75, probably. Unless Falco is one attack away from a KO (or at least from being far enough away to safely switch), using Ivysaur should be avoided at all costs. Falco players should make the most of this.
Charizard is a mixed bag--He's incredibly easy to juggle and combo, but small mistakes can cost Falco dearly in a lot of situations. If you grab Charizard in the middle of the stage, he should be taking a minimum of 81%.
The standard chaingrab to spike gives Falco one extra D-Throw before the D-Air. If he SDI's onto the stage, his tech roll is very easy to follow (either with a jab -> grab or another D-Air), and if he doesn't, a combination of his two mid-air jumps and Up-B allows him to barely make it onto the stage, where Falco can leave the edge and D-Air him again. Falco N-Air tends to be pretty safe to keep Charizard off, and it even functions decently as an approach.
Now, all of that sounds very bad for Charizard (and it is
), but Charizard has some great stuff going for him, as well. Charizard can juggle Falco quite well. U-Air stays out for a while and outranges Falco's D-Air. Charizard's tail flame doesn't have a hurtbox, so his N-Air creates a nasty win-win situation near the ground, as it sweetspots Falco if he tries to attack and sourspots him if he airdodges through it. At low percents, the sourspot combos into a grab, and at higher percents, it creates an awkward fall that must be teched, or Charizard will Jab reset into either full Rock Smash (45% damage and can be followed up until high percents) or a charged F-Smash (WILL KILL YOU).
Even if Falco does tech, it's easy to follow with Charizard's run speed (which rivals Meta Knight's), which gives him another grab to create that situation again. Speaking of run speed, it tends to put Falco players on edge when it comes to using Phantasm, since Charizard will catch up to it pretty quickly. Charizard's well-spaced N-Air beats Phantasm, and the threat of Flamethrower makes recovering a daunting prospect, since going to the ledge could get Falco gimped by an edgehog, and going above can lead to massive damage from Flamethrower (with proper fire movement, SDI'ing can be -really- difficult). Falco must be careful if Charizard grab-releases, as an instant spotdodge ends as soon as Charizard's instant F-Smash starts to hit. Charizard can shield a jab and U-Smash out-of-shield, too. Also, Charizard has enough range to grab you immediately out of grab-release, and Falco can only Jab or attempt to avoid an attack.
Basically, both characters can do really mean things to each other, but Falco's stuff doesn't really have to be set up at all, whereas Charizard has to put himself at risk in order to start most of it. I'd call it around 40-60, Falco's favor. It's tough for Charizard, but by no means unwinnable.
Overall, I'd say the matchup is 60-40, Falco's favor. PT has to work much harder than Falco to win, but it's definitely a matchup that Falco could regret not knowing against a competent PT.
