It would be interesting to see if what we get is a BIG retconned Episode 9.
Also, how MUCH unused footage of Leia / Carrie do they have? Several minutes worth? I woudn't think so. My bet is (if not some flashback scene) we will get over the shoulder and back shots of a stand-in / double for Leia with close up of her face. And are they going to give Leia a send off? Big death scene? May she RIP.
BTW: Carrie Fischer's appearance in TLJ vs. TFA looked worse to me, as if she were more ill. As a physician, I noticed the changes in the maxilla and nose the most. I bet you Fischer had dentures for a while, but something was really off with her nose in TLJ. Not just make-up, either.