Yeah, I mean, I can't say I agree with your actor suggestion list at all (aside from maybe Cassie, really seems to fit looks-wise), but then again I'm admittedly barely familiar with any of them at all. But you're totally right in that they kind of either need to be the right ages, or at least look it, y'know? You could get away with 15-16 year olds if they look young, but you really don't want like...highschool seniors for this. I mean, the Animorphs shouldn't be the same age as, say, the characters in Superbad, it'd feel all kinds of wrong.
I really struggle to think of anyone I'd really want to see in a potential Animorphs flick as any of the kids, certainly with anyone "current". I think ultimately it'd work best with close-to-total-unknowns, or total unknowns, like when they were casting Harry Potter. Helps a lot with the buying into it, too, for the audience, if it's not like "lol Dakota Fanning as Rachel".
The closest I've personally come to finding people I could see in the roles would be
maybe Joseph Gordon-Levitt back in the 90s, as a teenager, for Marco. Maybe. But again, not ideal. And Rachel, I've always thought Alicia Silverstone gives off a really "Rachel vibe" in the Aerosmith video for "Cryin'", both in looks and general attitude at the end in the diner. But even then, again it's kind of only in this video, and she'd have been too old there anyway. In 1993, haha.
Aerosmith cryin'Also randomly thought recently with the newer episodes of Modern Family, the kid who plays Luke might even work as Erek. Obviously very different characters, but seems like he could probably fit the part.
Also that gymnast girl, Gabby Douglas is it? Kind of gives off a "Cassie vibe" to me in interviews, that kind of calm/mature/peaceful-but-strong thing going on.
