yep. i just played yagami light a few times. dair is indeed a huge opening. fair isn't a huge bother. if he doesn't space well, shield and punish. if he does, just shield it. and then what? ike won't be able to follow up, because he spaced the fair to its maximum range. flamethrower out of shield can work at that point.
squirtle is just really quick, blah blah. i'm inclined to agree with kinzer on this.
the people that think ike destroys squirtle are the people that haven't really played a good squirtle...honestly, this all hinges on squirtle avoiding ike's strongest attacks. don't get careless, be opportunistic, use that grab game.
and charizard as advantage. one thing i noticed:
you know how ikes like to recover? from really far below right? and they'll usually double jump right before the aether. go down there as charizard and fair ike before, during, or after the jump. he won't be able to recover afterward. and ike can't counter attack or dodge you because he'll lose way too much height and die anyway. well, ike COULD if he wanted to bring charizard down with him. so that's why i suggest you only do this when you are at a healthy percent.
another thing with ivysaur is to tether onto the edge as ike aethers, and pull yourself up as he comes down. works best when you are off stage as well, because you will likely get hit by aether if you tether it as soon as you run off the stage.
you know what? i think all three pokemon have a slight advantage. charizard isn't bothered by ike's approach at all, just practice good shielding. ike cannot follow up on his best approach, the fair. zard can just shield it and flamethrower or get under ike when he full hops to negate the spacing. the nair can be shieldgrabbed, and nair to jab can be grabbed as well. so charizard can handle ike's approach well. defensively ike absolutely hates charizard's flamethrower. ike has no real answer to it. rock smash leads to a free grab if you land it. the only thing is that ike can outprioritize that rock with many of his moves. so you can't rely on rock smash as a counter in this match. but it's still useful. ike's most important move is the jab, and charizard outranges it and can grab it with a shield up.
ivysaur has been covered, it's agreed that he has the advantage.
feel free to keep debating, no match up is ever set in stone. i just want to move on here.
edit and i'll put ddd as slight neutral against zard and squirtle, neutral on ivysaur. ddd board doesn't care, and that's the gist of what we came up with in the ddd thread.