Fox is currently considering the following actresses for the role of Jean Grey in X-Men: Apocalypse, last played by Famke Janssen in five X-Men films:
Chloe Grace Moretz - likely the most well known of this group, having starred at Hit-Girl in Kick Ass and its sequel, the title role in the Carrie remake, and a number of other films.
Hailee Steinfeld - co-star of the Coen Bros' True Grit (for which she was Oscar nominated), she's also recently appeared in Ender's Game.
Elle Fanning - known for her roles in Super 8 and Maleficent.
Any of these three would be fabulous choices, though Fanning is particularly on the rise with an upcoming transgender role in the drama-comedy Three Generations that's seen a good deal of press.
As for the role of Cyclops/Scott Summers, the studio is looking at lesser known actors but their short-list includes Timothee Chalamet (who played the young Tom Cooper in Interstellar), Ben Hardy (EastEnders), and Charlie Rowe (Red Band Society).
The new film will center on the romantic relationship between Jennifer Lawrence's Mystique and Michael Fassbender's Magneto, and could very well set the tone for whatever occurs between the two characters cast for the X-Men's most famous couple.
The real question though...if Hugh Jackman returns as Wolverine, I wonder how they'll handle his relationship with Jean this time around?