X-Men 5 would be loosely based on the classic story X-Men Days of Future Past.
The X-Men
Charles Xavier: Confident that the X-men can look after themselves Xavier is spending less and less time with them and more and more time with the students on Muir Island.
Scott Summers: Devastated by the death of Jean Grey Scott leaves to "find his inner peace". He becomes a sailor working for captain Madelyne Pryor.
Ororo Munroe: Since Scott has now left Storm has become the new field leader for the X-Men, She feels the weight and responsibility of leadership.
Pyotr Rasputin: The gentle giant of the team, Colossus has become like an older brother to Kitty, although Kitty sees more than just a brother in him...
Kurt Wagner: Nightcrawler's self esteem is tested as Kitty is finding his appearance... difficult to adjust too. however eventually Kitty learns to look behind looks and the two become good friends.
Logan: Wolverine is still the loner of the team but is learning to trust his team mates more. He is shocked when he meets the brotherhood and realises that Sabretooth knows him from before he lost his memory...
Kitty Pryde: The Youngest member of the x-men, Kitty only just managed to persuade Professor X that she should be an X-Man and not a student on Muir island. She is a daughter figure to Storm, a little sister / love interest to Colossus, Sidekick to Wolverine and towards the end of the film, best friend to Kurt.
Sean Cassidy: Sean Cassidy has left the X-Men saying he is too old for fighting now and become one of the teachers on Muir Island.
The Brotherhood
Raven Darkholme: Mystique has returned from her original role in Magneto's Brotherhood and is now leading the new brotherhood. She has a plan to assassinate anti-mutant crusade senator Robert Kelly.
John Allerdyce: One of the brotherhood, Pyro can manipulate fire.
Victor Creed: Sabretooth know Wolverine before he lost memory. He believes strongly in survival of the fittest.
Fred Dukes: Blob was considered as a recruit to Magneto's brotherhood but was captured by the MRD he was broken out by Mystique's brotherhood and is now one of their most loyal members.
Rogue: Not truly evil Rogue was raised from birth by Mystique and feels it is her duty to support her surrogate mother. Rogue has never been able to make skin contact as it results in her stealing their memories and in the case of mutants, powers.
X-Factor:
Lucas Bishop: The leader of the future's X-Men, renamed X-Factor, he is one of the last surviving mutants and has a plan that involves sending Kate Pryde to the past briefly to stop this future from ever happening.
Rachel Summers: The daughter of Scott Summers and a red-headed telepathic. It is implied she may be one with the phoenix force.
Kate Pryde: Kitty Pryde in the future. She remains fairly unchanged except she has gained an optimistic attitude and she prefers to be called Kate now not Kitty. Forge creates a machine that allows Kate to travel briefly to the past to tell that X-Men about the assassination attempt on Kelly's life and the events it causes if it succeeds.
John Silvercloud: The man named Forge is the master of machines and manages to create a machine that projects Kate back to the past for a short length of time
Erik Lensherr: Erik has survived but is now crippled like Xavier was/is. He is the old man / mentor of the team but dies fairly early in Bishop's plan.
Scott Summers: Now using the name Basilisk, Scott Summers is the only mutant in America still running loose. (for the purpose of this movie he plays the role of Wolverine in the future during the days of future past original story)
Misc:
Robert Kelly: An strongly anti-mutant American senator whose death will cause the days of future past timeline. He's not an evil man he's just misguided.
Madelyne Pryor: The captain of a seafaring vessel. At first Scott mistakes her for Jean reincarnate and soon realises he loves her but isn't sure if he's willing to cope with another relationship. He joins her crew as something to do while he searches for inner peace
Sentinels: The sentinel robots have been reactivated in the future in response to the assassination of senator Kelly. within 20 years time the sentinels are in control of America ran by Master Mold. The Sentinels are a similar but upgraded model to those in Uncanny X-Men 1
5th in my X-Men movie series:
1:http://www.comicbookmovie.com/fansites/chrisstuff/news/?a=35837
2: http://www.comicbookmovie.com/fansites/chrisstuff/news/?a=35874
3 and 4: http://www.comicbookmovie.com/fansites/chrisstuff/news/?a=35974