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.
Which is by no means a given in the post-Rebellion era. With Lucas no longer the one controlling Star Wars (at best, he's a creative consultant now), the new writers and producers of future productions are free to change that no attachment rule and even the rule of two for the Sith--and it really stands to reason that after thousands of years, both the Jedi and the Sith have undergone changes in their policies numerous times in the past and will do so in the future, IMO.
But regarding Legacy
, even if the Skywalker line is revamped in the new movies, it really shouldn't effect it too much. We're still two or three years away from Episode VII (perhaps four with Abrams directing it), so that should be plenty enough time for the upcoming second volume of Legacy
with Ania Solo (and eventually Cade) to tell its story and wrap things up before then.