Regarding the 'changes to the lore' that First Class as a movie makes, personally I don't see the problem with them. If we mean the books and their lore, then 95% of the X-Canon is garbage, really, with choice nuggets here and there. If we mean the films and their lore, the filmmakers already stated their intent to go out of their way and ignore X3 and Wolverine, which, frankly, is the best decision they could've made.