it's neutral because gaw has the same 'rating' yet charizard was neutral. so to be consistent, i changed marth's as well. it could easily go both for disadvantage as well, iirc the consensus was 40-60 and maaaaaaaaybe 45-55. it's just for consistency is all. regardless pt overall is still slightly disadvantaged either way.
charizard and metaknight are on fairly even footing. charizard is one of the few characters in the game that can consistently counter/outprioritize mk's specials and force him to play straight up. rock smash and ftilt will usually go through mach tornado, flamethrower and rock smash cancel drill rush, although zard will still get hit from DR when he uses rock smash. and zard can shieldgrab mk out of his glide attack. at that point charizard can focus on playing defensively against mk, and he has a variety of options there: great grab game, flamethrower, good spacing attacks, rock smash on occasion. it's imperative that charizard have a great defensive game, charizard in the air is baaaaaaaaaad for pt and gooooooooooood for mk. luckily charizard has a variety of defensive options and can QUICKLY rack up damage with ft/rock smash/grab games and kill at low percents all the same.
squirtle isn't truly neutral imo, but some others here think so. i've changed my opinion slightly since we went over mk months ago. but squirtle's grab game works well, it's similar to metaknight's, but squirtle's is a little trickier/unpredictable since he can shellshift it and all that. shifted grabs have VERY deceptive range, all the better for getting a quick dthrow in when mk is at high percents. it'll kill mk at around 110-115%. ftilt is very quick and links into jabs. hydroplaned usmash kills mk at around 80%, even more lethal on stages with low ceilings, stadium 1 for example. in fact all three pokemon can kill well vertically, while mk rarely ever kills vertically, so that's a good counterpick. regardless, hydroplanes are VERY quick and VERY unpredictable if the trainer isn't just spamming it early or something.
if squirtle can keep the match mainly on the ground, he can keep it close...but still in mk's favor, imo. reason is that squirtle is really pretty dominated in the air and mk enjoys gimping squirt. and the ground game is neutral, at best. mk's dtilt will screw with a lot of stuff squirtle tries to do. i brought this up earlier and was waiting on people to comment on it but no one ever did so...it hasn't changed. maybe it'll change now that your highness has brought it up.
ivysaur is okay as long as he can keep the fight mainly grounded, spaces well and doesn't get too near the edge, risking shuttle loop or an easy gimp. it's kind of like squirtle, except ivysaur plays a much better spacing game. razor leaf is alright, but nothing to depend on. ivy has solid grab range, although it's pretty laggy if it misses. pivot grabs are alright though. but shieldgrabbing mk can work occasionally. ivy's grab game is okay, but definitely not as good as zard's. ivysaur has more trouble with mach tornado than the other two, fsmash is the only move (i believe) that can solidly outprioritize tornado consistently.
playing a sort of 'midranged' game seems to fit ivy best here, carefully keeping mk away from itself yet keeping him at a sort of midrange by pressuring with spaced bairs, ftilts, dtilts, and the occasional razor leaf. mk is definitely not going to be able to waltz right up to good ivy and start hacking at him. don't forget bullet seed, a dodged dash grab will make mk eat like at least 20% damage. bullet seed is actually an excellent punisher. it's like a spot dodge -> dsmash, but it racks up damage instead of killing. most of mk's attacks are lagless enough that bullet seed won't completely ****, but it's definitely something for mk to be wary about. if mk makes a mistake, he WILL be punished.
mk FEARS uair and usmash, luckily for him they are not easy to hit with. but if ivy does succeed, expect mk's to die at like 50-70%. the reason ivy is disadvantaged is because he is very easily gimped and ivy can have a tough time setting up its defenses again if mk gets inside and penetrates.
overall i'd say it's like 45-55. charizard is pt's main workhorse in this matchup, you can expect some pts to use zard for both their 1st and 3rd stocks, and split the second with squirtle and ivysaur. there are other ways to do it, but the point is that it'd be neutral 2/3 of the time and slightly disadvantaged for that second stock.