Suki is definitely in there, though I don't know about the rest of the Kioshi warriors. Good news: I saw a new trailer just last night and it looks like they are going to have at least some of the comedy and Sokka's goofiness in there. Also, Momo is certainly in there too.
I am going to go watch it too, even if the acting isn't so great. I am a bit of a sucker for good special effects. Though I am going to wait a few days for when the theaters aren't packed full. Too many people make me paranoid.