That's sure, the savior told it already. I think no one can be sure of who will meet Lucille. I think they'll choose the predestinated after reading what the fans say and killing someone never mentioned
Negan will probably kill one of Rick's group. According to the comic book, Glenn gets brutally beaten by Negan and is shot in the head when zombified, but that's IF AMC is going by the comic book, seeing as Carl eventually did get shot in the just like how he did in the comic book and how Jessie was devoured by walkers.
They are for sure doing the scene where Negan kills a member of a group. The only question that anyone had had in months is if t will be Daryl or Glenn. So much evidence is pointing toward Daryl though.