I don't think it's the worst idea I've heard, it's definitely better than Chenoweth as Fran in PROMISES, PROMISES. She's very funny and I can definitely buy her as a woman who "meddles" for a living, but I don't know if she can pull off some of the moments where she has to be a bit more grounded. And yes, her "Before the Parade" was unremarkable in the concert, maybe if the song comes out from an actual acting moment it'll be stronger.
On a completely different note, did Angela Lansbury ever play Dolly? I was thinking of whom I'd love to see in the role, and she was the first one to come to mind (obviously I mean when she was age-appropriate for it).
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"