The council has notably been including Sophie and her friends lately. I mean, five of them got appointed as regents. Regents.
If the council is learning to rely on Sophie and her friends because of their insight, that also means there's a good chance one of them will end up on the council. Right?
My theory is that Fitz will be the one to become a council member.
Why?
Reason #1: Fitz's middle name (Avery) literally means "elf council."
Reason #2: Councilors are not allowed to marry. You know what that means! *chanting Sokeefe*
Reason #3: Fitz might feel the need to at least try to get a spot on the council so he can save his family's reputation. After Alvar, they aren't in the best spot.
Reason #4: Fitz has been through more than just about anyone (besides Sophie and her friends) and would most likely be a good member like Oralie, Bronte, and Terik.
This would also be a good way to end the love triangle. It would end without Fitz being heartbroken, but learning to accept the fact that he cannot marry.