#1 Charlotte Flair
If Charlotte Flair isn't in a title match at the actual PPV, then she's a lock to not only make it to the final four each year but also win the whole thing. The problem with her winning it, however, is two-fold. She's such a big star that she doesn't need to win the match in order to get a title shot at The Show of Shows.
In order to get prior title matches, she simply walked to the ring and said "I'm Charlotte Flair" and then on two occasions (at MITB 2019 and against Asuka prior to 'Mania) she won the title.
The Rumble win should go to someone who truly needs to win that match just in order to receive a title shot. That line of thinking applies to both matches. The other problem with her winning this year's match involves the current Champions.
The two women who hold the titles are people with whom Flair has battled numerous times. She's fought with Bayley all throughout 2019 for the SmackDown Women's title and we know the history she has with Lynch.
Flair and Baszler are likely the two favorites to win the match as long as Ronda Rousey doesn't decide to return and shake the whole thing up once more. Rousey also has unfinished business with Lynch due to both losing her title to The Man and for not having a singles match with Lynch. The Queen may or may not win it, but she's definitely going to be one of the final women left standing in the match.