I don't think the younger brother can actually fly. I think he's a power absorber. Notice that he only flies when he's around his brother. He can only paint the future when he's around the artist. I'm thinking that on his own, he's nothing, but when he's got other people with powers around him, he can duplicate them.

I see your point about too many people though. From what I've heard, they're supposed to have a total of ten of them (whether that includes Syler or not, I don't know.) If that's true, then as of this Monday's episode we've got 10. (Cheerleader, Hiro, flyboy and his brother, artist, freaky mirror chick, her husband, her kid, mindreading cop, and the bald black dude that Cheerleader's dad uses to wipe their memories when he kidnaps them.) I suppose the waitress in the diner would make 11, if Hiro actually manages to go back and save her, but I'm thinking that's not going to happen.