Again, so far there's nothing official. All we know is that Psylocke is in the books and she WASN'T resurrected. She's being treated as though she is a new character altogether, especially not one who came back from the dead.
As for Apocalypse, during Nick Spencer's run his first (and only) 12 issues lead up to a sort of "4 Horsemen of the Apocalypse" type dealy and the very end showed Sinister bowing down to the Apocalypse-dressed mannequin from earlier in the Ultimate X-Men days. It was left at that and Brian Wood took the story in a whole different direction and says that he doesn't plan on revisiting Spencer's plots. However, around these forums people are piecing together all little hints and whatnot theorizing that everything that's happening now with the mutants is still part of Apolalypse' plan. Again, no real word on this, just fan speculation.
As for Apocalypse returning from being erased from existance, he hasn't. At least not officially. All we have is Sinister and a mannequin. The "ghosts" if that's what they were, during Spencer's run, can easily be explained as a whole different threat in the form of some psyhic mutant and even Sinister himself is being duped into thinking that his Lord is talking to him just like Rogue thought that Xavier was talking to her.
It's all vagueness and mystery, and besides the point since Wood said he's not revisiting any of it.