@war_killer: The Kitty Pride time travel was a deus ex machina/comic-book homage.
It was a deus ex machina in the sense that Simon Kinberg came up with a silly reason to explain how the surviving X-Men are able to travel.
It was a comic-book homage since-in the Days of Future Past arc-it was Kitty Pride that traveled backward in time, not Wolverine. Wolverine was the time traveler(in the film) since he the protagonist of the X-Men film franchise, but the movie honored Kitty by having her be the reason he time travel in the first place.
*All of your other questions are the same ones I'm asking as well.