I think Chanel # 3 or Chanel # 5 might be Boone's twin sister/the red devil.
It would be fun if they showed the other endings with the other killers and their story behind why they did it.
To me, the only evidence that I can find that Chanel #3 isn't the killer is that Boone was actually on the phone with his twin sister (The second Red Devil whom we have no idea yet). So if #3 was the Red Devil, she shouldn't be acting like that when she encountered with Boone especially in public.
These are the only proofs that #3 can't be the killer and completely destroy her theory. Also, if we think well, no one between #3, Hester, #5 and Chanel can be the killer because during the time of Hester's death,the twin sister killed Boone.
There goes my "Hester is the Killer" and "Chanel is the Killer" theories :(
^ It could possibly happen at the same time as Boone's death but I don't think it's the same time.
If Hester was the Red Devil: After she stabbed Boone at the hotel, she went back to the Kappa house. The Chanels greeted her nicely and invited her upstairs to Chanel's closet where the scene of Hester revealing that she's not actually pregnant.
She couldn't have gotten there in time. Nor could Chanel. Or, any of the Chanel's for that matter.
^^ Well, it for sure happened after Earl's death and after "Libby's escape".
Hester was with the Chanels when Boone came back home and talked with his sister and Gigi.
Yeah, so it couldn't have been her.
I am currently rewatching the early episodes. I noticed that in the episode Hell Week when the Chanels found Chanel #2's body, Hester came in the scene and told the Chanels that since her father died, Hester's mother made her kiss her dead father's body and that's how Hester was obsessed with death. During that scene with Chanel's #2 body, Hester told the Chanels ways on how to dispose the body of Chanel #2.
About that, Hester mentioned that she had a father and a mother. So that made me wonder, maybe she is not the bathtub baby after all or the second Red Devil. Nor is Grace or Chanel is the Red Devil. Chanel has rich parents and we already know who Grace's biological parents are. Unless Hester was lying about her parents and made up the story of how she was obsessed with death.
What do you think?