Trudy, Grace, Tsu'tey, Quaritch, and Eytukan all supposedly died, along with many other unknown human and Na'vi characters. Two minor characters that were identified as dead are Lyle Wainfleet and Sean Fikes. Grace is returning to Pandora somehow in the sequel, and rumors are brewing that Quaritch will be ressurected, meaning he will most likely return. Tsu'tey's fall off of the ship in which he was shot by a human was unsurvivable- it is impossible for him to return. If you watch Eytukan's death closely, his color changed to a strange shade of gray with a tint of blue, his voice was a whisper, and he was weak. He obviously died and will not be brought back to the Avatar movies. Michelle Rodriguez, who portrayed Trudy, has not signed on for Avatar's sequel, sadly, and had hinted that Trudy would die like the rest of her "bad girl" movie characters in an interview before the movie's release. Fans are making up stories about her escape from her ship in a parachute and being found by Jake and Norm, who put an exo-pack on her and had Mo'at transfer her into an avatar body thata had started its growth 6 years ago, but James Cameron never uses stories from fans, and her survival is near impossible. The thought of Trudy returning is an excellent thought because of her incredible piloting and fighting skills and delightful humor, not to mention her charming good looks, but the only reason she might have survived was because of an unseen parachute jump, in which she probably would've died anyways beacuse of the human-killing air on Pandora. There is a 99% chance she will not return.