Can she pull it off? Absolutely. I would even consider her the frontrunner at this point. Is it a sure thing? No. I definitely think it will come down to O'Hara or Block. I also foresee the love for certain productions being a factor, as a large swath of the winners in acting categories over the past few years have tended to come from shows that received lots of love in other categories. The Tonys have enjoyed "sweep" years in the recent past. While neither of these productions (Cher or Kate) have opened, I'd assume O'Hara would have the edge there.
I'd love either of these two wonderful talents to win, and I'd also add Samantha Barks to the mix, whom I think elevates Pretty Woman exponentially. I predict the nominees will be Barks, Block, O'Hara, Pitts, and a dark horse from The Prom or something unannounced (Noblezada in Hadestown?). I'd add Lilli Cooper, whom I loved in Tootsie, to the mix, but I feel like she will be petitioned for Featured.