I have posted about this previously but was unable to get any traction. If you go back and listen and/or watch any youtube video releases concerning Avatar, or read any blog articles that quote Cameron, Staggs, Landau, etc., there are some that hint at nighttime entertainment offerings in this section of the park. Of course, it is not expanded upon to any degree.
I would think that since this expansion is being built to act almost like some type of umbilical apparatus to keep guests in DAK at night, that there would be some type of outdoor live entertainment aside from the fact that the very land itself will come alive at night via the bioluminescence of the trees and plants. The new Rivers of Light show coming to this park should be great but will only accommodate so many guests. I think that they will need more beyond that show, and Pandora should be a targeted location to provide this as the backdrop in this expansion - you know, floating mountains and all - will be both unique and phenomenal.
As far as cast members dressed up to look like the Na'vi characters, that will be tough to reproduce. People on stilts, IMHO, will not provide a realistic enough representation of what these creatures truly look like. Maybe if the show is presented as some type of human reenactment of Na'vi customs and the cast members are dressed up to resemble Na'vi characters, that might be one approach. I will just be curious to see how the imagineers tackle this park of the expansion, including any dining locations. Staying on theme with some of these offerings should prove a challenge, and one that I am interested in seeing how they handle them.