I have a feeling Legacy will have to be redone, since we've seen references in the legacy comics to the current eu,it will need a new background continuity. Since cade is descwnded from ben, who's descended from Luke, and Mara, and there's a good chance that in the new movies, Luke will be following the no attachement rule.
I don't recall Legacy ever establishing that Cade descended from Ben. I mean, I assumed that, but I don't think it was ever stated. Outside of his last name and the Force Ghosts of Luke, Mara, and Anakin (I think Anakin and Mara might have been drug induced hallucinations), we know that Cade is related to them, but we don't know how.