Uzo Aduba reads way too young for Caroline. She would make a brilliant Dottie which is one of the great underrated supporting roles in the musical theatre canon. Caroline may be 39 (Aduba reads early-to-mid 30s), but she should look older because of her situation.
I adore Audra McDonald and after seeing her as Billy Holliday will never say she isn't capable of turning in a rougher characterization than what I usually associate with her, yet I don't think she would be an exciting choice for the part.
I really like the idea of Chandra Wilson sort of graduating to Caroline.
"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"