Re: Timeline(s) in Apocalypse
I think Apocalypse and his Horsemen will be the time travelers. Maybe Cable is one of them. Like Galactus' herald who recruits.
Maybe the DOFP timeline is where Apocalypse rules after the Sentinels have wiped out the X-men and changing the future has stopped that so he sends Cable back to start his empire in the world without the Sentinels by recruiting a group of Horsemen to pave the way for his entrance into the new timeline.
Xavier is able to convince Cable not to do this and help keep Apocalypse trapped in the fading timeline.
Make America Great Again is to 2016
The South Shall Rise Again was to 1868