Big Advantage: Ike
Ike can't do anything about Din's fire, and it forces him to approach. Once he approaches he has to deal with one of the best defensive games in Brawl. Overall this character has the most start-up lag on all his moves, making a lot of Zelda's quick casted moves easy to hit on him. He also has an above average build, making it easier than average to kick him. There ARE tricks good Ike's can do to beat a Zelda, but for the most part, its going to be a steep uphill battle for him.
Main: Zelda
I disagree. Din's fire does nothing to Ike except for shutting down his QD game somewhat... somewhat. Whoever draws DF/QD first wins. But that's not the entire fight.
Ike has a pretty big sword, and while it may be slow, it outranges a lot of Zelda's defensive game. He can come at Zelda and your basic dsmash instinct won't work on him, if only because he's out of harm's way while he's attacking you. He doesn't need to get as close to you as Bowser does (and I agree that Bowser is at a big disandvantage). I'll give an example of what I'm trying to say: Ike's fair approach.
Ike's fair gives Zelda some problems. If he short-hops it she can usually catch him before he lands it with a usmash/hyphendash, and if he full-jumps it Zelda can sometimes Din's (because usmash won't work if he full-jumps). Ike's Fair hits Zelda whether full-jumped or short-hopped, that's how big the hitbox is. Unfortunately for Zelda's counters to this approach, only an idiot would keep jumping in with a fair all the time without spicing it up. And even if he doesn't spice it up, sometimes the upsmash won't make it out in time and you've just eaten a fair. Zelda's counters on this aren't even close to reliable if you have a any hesitation whatsoever.
Also, his fair may take a while to start up, but the lag isn't too bad. If you try to avoid it and rush in to punish, you may find yourself eating a jab combo. His fair outranges all of Zelda's moves save Din's, but if you miscalculate even a little trying to stop his approach, you'll get a big bronze sword to the face.
With that uber-long explanation on just one of Ike's approach options, I'd like to make it a bit more brief. Zelda's quick-casted moves won't hit Ike if they can't reach him, and if Ike has any sense of spacing you won't be landing any dsmashes/fsmashes/dtilts/etc. And although he may be larger than some, Ike wins in the air against Zelda, period. Every one of his arials outranges hers, save uair, and uair is tricky to land on an Ike (Eruption is a good uair punisher too, I might add). And an arial approach against a grounded Ike isn't the best idea. You won't be landing many kicks on him. I'm unsure as to what the actual matchup is against Ike, but I know that it isn't a steep uphill battle for him.
