"My plan was First Class, then second film was new young Wolverine in the 70’s to continue those characters, my version of the X-Men. So you’d really get to know all of them, and my finale was gonna be Days of Future Past. That was gonna be my number three where you bring them all… because what’s bigger than bringing in McKellen and Michael and Stewart and James and bringing them all together? When I finished the Days of Future Past script with it ready to go I looked at it and said, “I really think it would be fun to cast Tom Hardy or someone as the young Wolverine and then bring it all together at the end." The Link: https://io9.gizmodo.com/fox-wanting-days-of-future-past-right-after-first-class-1835148286 I think Matthew Vaughn aimed at casting a "younger Wolverine" before they would put Hugh Jackman into cameo mode in FC. It's obvious that FIRST CLASS is a soft reboot and a second timeline/alternate universe, so people should not bother with the clear incongruences between the 4 FC/DAYS movies and the original 4 X-Men movies. As simple as that.