2. Magneto's Original Assassination Plot Will Be Foiled
The trigger event that sends the world into a spiral of apocalyptic doom, and eventually leads to the sentinels exterminating the X-Men in the future (or at least a good number of them) is of course the Senator Kelly assassination - though not in this film universe, given that we've already seen Kelly in Singer's X-Men films. So, regardless of who replaces Kelly as the target - and thus whose death Wolverine is "sent back in time to thwart" -presumably there will necessarily be a similar central plot in Days Of Future Past. Logic would suggest that Wolverine succeeds, not only because he's Wolverine, but also because the emergence of Apocalypse requires a complete change in ideology from Magneto that sees the opportunity for Apocalypse to appear and make a play for the Earth, in order to wipe out humanity. That would require the appearance of an alternate future where the Sentinels do not rule, since the Age Of Apocalypse timeline is very reasonably considered the antithesis of the events that happen in the future of Days Of Future Past where the mutants are exterminated and pushed into hiding. The two futures cannot co-exist, so Magneto cannot set the Sentinel wheels in motion, without inspiring a future in which Apocalypse attacks, so it seems Singer has just confirmed what we can expect at the end of Days Of Future Past.