I agree that Tris, Charlotte and Denise are guaranteed.
And Lisa+Lauren are the obvious names on the chopping block, maybe a cameo goodbye but certainly not a whole lot of content for them.
Emma, personally i really don't care for her, she was like a rash i couldn't get rid of

, but RC made her more integral to the story than most others not named Tris and Charlotte... so i don't know.
I hope so too, Bea is my favorite character outside of the family(maybe better than some members of the family), so i hope she gets a strong ending.
With the fact that both Charlotte and Tris already know about her and the MC, she's friends with Triss and already hangs around the house... i'd say her story is already in a rather advanced stage(unlike say Lisa or Lauren who still need to be introduced to the family).
Here they already know about it, it's all about convincing them to share...
Tris didn't take it well at first... but i'm still hopeful.
With the way the story was originally going, and knowing how RCs previous game had a ton of endings, i'm sure a Tris+Bea ending was a reality.
I just hope it isn't one of the choices that gets cut.