Will the Four Horsemen be featured in X-Men: Apocalypse?
According to the following image posted by Bryan Singer, they will.
Singer posted an image of the X-Men: Apocalypse script were a few sentences can be read, which mention the Nile as well as The Four Horsemen.
There are many different incarnations of The Four Horseman which include:
X-Men: Apocalypse has a May 27, 2016 release.