We know that Zoe Saldana and Sam Worthington have signed up for a trilogy – so I assume that we will see them in Avatar 2 movie. It is rumored that Giovanni Ribisi will return as Parker Selfridge, and Stephen Lang will return as Quaritch, (resurected ore cloned somehow – as you know he was killed in the end of Avatar).  In an interview, Lang says “It’s not over while I’ve still got DNA” strongly hinting towards a possible resurrection of Quaritch. Recently it has been confirmed that Joel David Moore will return as Norm Spellman. Also, at the Golden Globes, Sigourney Weaver (Ghostbusters III – 2011) hinted at the return of her character, Dr. Grace Augustine, in some form, saying, “If you look at the footage, I don’t really… I go somewhere, right? It’s science fiction. Anything can happen.”  The actress later confirmed that she and Cameron had agreed to bring Grace back, commenting, “I’m actually in the tree.