It's already been said that it's a "long forgotten story" from the past or whatever. So Rahne will be in it, but not because she's been brought back. Of course by then who knows, maybe we find out that Rosenberg's run was some kind of trickery and she's been working in a Starbucks the entire time with the owner of Harry's Hideaway.
That being said, very strange that they'd use Magik's new sword on this then. Maybe parts of the story are in modern day.