About the title, if they don't want to use "Age of Apocalypse" because transformers and Avengers are already using the "Age of " for their films.
How about "X-Men: The Apocalypse"? Its simple yet striking.
X-MEN RI5E' MUTANT OF THE MONTH | CYCLOPS | PORTRAYED BY JAMES MARSDEN
"Stay away from my girl" - X1
"You don't say that, we gotta go back" - X2
"Not everybody heals as fast as you" - X3
"Easy pal" - X4