Well, I think the hilts and things and holocron and costumes are just things you collect for gameplay sake, and not part of the canon. I mean, if you go by the Wii series, you get random jedi holocrons littering around almost everywhere! Not to mention crystals and saber hilts and clothings, and the connection to assassain's creed in some version.
So the only retcon is the part about the alliance formation, the rest are just gameplay cakes. Read the comic for the core canon-isque story.