Re: X-Men: Days of Future Past Speculation
My guess as to how the timelines will work is that Magneto and the Brotherhood kill a major public figure in the 1960s on camera which leads humans to flip out and build sentinels. This creates an alternate post apocalyptic Days Of Future Past timeline that runs parallel to the X-Men Trilogy.
Pervious characters from the X-Men Trilogy timeline are different from those of the DOFP timeline so the ones that died or were depowered could still come back.
All aboard the Pork Chop Express!