With regards to Marvel potential getting some X-Men characters back.
Keep in mind that X-Men Apocalypse and Old Man Logan are the last time we are going to see the current actors play those roles.
Jackman, Mcavoy, Fassbender, Hoult, Lawrence, Stewart etc, won't be coming back for any future X-Men movies.
This potentially frees up the major X-Men players to be recast and used in an MCU property.
While Fox goes ahead with Deadpool, Gambit and their New Mutants movies.
Again, this is speculation, but it could happen if Marvel and Fox make a deal like Sony did for Spider-Man.
Has there been any actual confirmation that Mcavoy, Fassbender, Hoult and Lawrence are all done after this movie? All I've seen are rumors based on the fact that they had 3 movie contracts and that Lawrence might want to move on.
Regardless, there's no way Fox would keep the rights to the X-Men universe and give away the rights to Magneto and Professor X, even if they don't currently have plans for them.