Huh?
That doesn't make any sense. The divergence doesn't happen in 2023, which is when Kitty sends Wolverine's mind back in time. It happens in the past in 1973 from the moment Wolverine's older mind takes control (switches places with, whatever) his younger self.
That's back in 1973, so the events of DoFP didn't happen in the original timeline. Yes, we've all asked questions like, 'then in the OT how did Professor X start to hope again' and 'then in the OT how did Magneto escape', but the how doesn't matter. It must have happened, just in a different way.
So everything that happened in 1973, from the moment Wolvie wakes up, it's a new timeline.
Yes, we don't see the change to the future until Mystique makes her choice at the end of the movie, but that just shows the fact that most things that did happen in the OT will/have still happened in the new timeline. Sure, that statement can't be said for everything, but due to the 2023 wake-up scene we know that much happened the same way. Same characters, played by the same actors and actresses, in the same mansion, with the same looks, with the same relationships, etc.!
You explain that DoFP is chronologically last, but that's only partially correct. Yes, both 2023 scenes, the one with the battle against the Sentinals and the one when Wolvie wakes up, happen last chronologically, but all of the 1973 stuff happens in 1973, which means it's inbetween Origins, which happens post 1973, and X1.
As far as your Universe B, you need to add the Wolvie wake-up scene after Gambit for it to be correct, because that scene happens in the new timeline!