There is no reason for Genesis to be in the game as long as the re-chaining scene in the Lifestream is not made longer and shows what he has experieced outside of the reactor and stuff. Other than that they might hint "G" maybe once or show Banora and stuff. Genesis is supposed to be a ghost during all those years. Nothing except some rumors and infos hidden in Deepground.

They could add Cissnei. I want to see more Cissnei.