Sierra will get her nomination but I don't see her getting close to winning.
As for Faith, I think Faith is AMAZING in Catered Affair but she is not given any great songs to sing in the show.
Jenna blew me away as Dot in London but Patti will probably walk away with the Tony as this is the role she was born to play and as a snub to Brantley who loved Bernadette as Rose but didn't rave about Patti's portrayal.
To figure out who will win, try thinking like a typical Tony Voter and this will be their rationale: Patti is almost 60 years old. She really deserves that 2nd Tony. Jenna and Sierra are just starting out their Broadway careers. I already mentioned why Faith won't get a Tony.
"It does what a musical is supposed to do; it takes you to another world. And it gives you a little tune to carry in your head. Something to take you away from the dreary horrors of the real world. A little something for when you're feeling blue. You know?"