I would say the Phalanx... But only Jubilee and Sabertooth (I think,) would be fair game to be on the rescue team, as Emma Frost and Banshee are dead. Those four were the heroes in that storyline, and it led to the rescue and formation of Generation X.
I would say Bastion and the Prime Sentinels... And play it out like they did in the comics. He hates mutants and would want to kill them all... Even at the risk of harming humans in the process. Starting with wanting to destroy the X-Men, Jubilee would be captured and tortured by Bastion, Prime Sentinels, and his soldiers. It would give her big development and be certain to showcase her powers during her initial fight and escape attempts. Unknown to her at first, the other X-Men (Jean, Scott, Kurt, Storm, etc,) would be captured by him and soon be killed... Until she manages to free them by unlocking their cages by hitting the control room computers while Bastion tried to probe her mind for info on mutants. The team would escape and not realize that Jubilee was there at all. They would all fight Bastion and the sentinels through much of the film... Tons of power combos and saving civilians for a change. Television reports would show rescue scenes and secure the X-Men as good guys. Younger mutants that could possibly form Generation X would get power cameos. Jubes would befriend one of the guards and in turn, would be released. She would join the rest of the team in a final stand off against Bastion. The film would end with several of the main team deciding to lead/teach the younger generation of mutants... While Xavier still overlooked everything at the main location.
