I think I may have the Bankhead episodes of the Lucy-Desi Comedy Hour somewhere back in my tape library -- hilarious. "STRAWBERRIES!!"
Both Bankhead and Hopkins were dead by the time of the movie version in '74, so, NO, I guess they wouldn't have been the best casting choices (and would have required even more gauze on the lens than Mme. Ball).
Bankhead would seem to have been born to play Vera -- she may have even been a model for the character (perhaps she did the play in stock somewhere in the 50s or 60s, like half the actresses "of a certain age" during that period).
I don't remember seeing Miriam Hopkins in anything after her Bette Davis run-ins in the 40s so I have no idea what she might have been like even at the time of the play in the late 50s.
Lansbury was the only choice for the musical role and its criminal she didn't get a chance to play it (she says she was never even offered it).
"What a story........ everything but the bloodhounds snappin' at her rear end." -- Birdie
[http://margochanning.broadwayworld.com/]
"The Devil Be Hittin' Me" -- Whitney