Whoopi definitely couldn't do OSAGE at this point, but she'd make a great Mattie Fae indeed.
I think Viola Davis or Tonya Pinkins would make excellent Barbaras.
"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"