Possibility 3: Asuka wins

Many people would enjoy it if Asuka secures her first main roster title at TLC. However, what makes it even more exciting is that the prospects for WrestleMania would be thrown wide open. She's the wild card in this match for that reason.
An Asuka victory would make the Royal Rumble a lot more unpredictable. Three possibilities would then branch off from her title win.
Possibility 4: Asuka wins at TLC, Charlotte wins the Rumble, Asuka vs. Becky

With no title shot on her hands, Charlotte Flair would find herself in the Royal Rumble, but not as the odds-on favorite, because Becky Lynch would also be competing in the contest. Nevertheless, Charlotte Flair would still prevail to set up her WrestleMania match with Ronda Rousey. In the meantime, Asuka would take on Becky in an equally exciting first time ever (on TV) singles match.