ehhh...I mean, sure, anyone can make up a backstory if they've got ideas for it, but a canon like SW means future shows or whatever could still roll in and stomp all over your great ideas. that said, I've met a scant handful of fanfic authors in my *cough* decades of fandom who actually had the chops to come up with lore that fits the character and is convincing enough. most fanon is stupid shit like pop-tarts. I don't know the character but I'm guessing OP's point is that there's room for a smidge of lore which any and all fanfic writers could then run with.