Using the Ultimate X-Men as a template would be stupid because the Ultimate X-Men run was inspired from the Fox-Men to begin with. Just use Claremont's run. It's not like Fox did. Giant Sized makes the most sense. It's how Marvel rebooted the X-Men line after a lackluster start in the comics. Why not do that for the movies too? Plus its global cast(we really need a better Chinese mutant... Jubes and Xorn just really don't cut it) aligns better with modern movie demographics. Maybe use the Lady Mandarin Psylocke reworked as Guanyin, and use Betsy Braddock in the Captain Britain line instead?