Just a comment on the age of Sally, in Goodbye to Berlin (the novel Cabaret is based on), Sally Bowles is 19 but looks 25 because of the way life has treated her already. Yes, the musical alters the story and character quite a bit, but I think the actress playing Sally should be in her 20s. An older Sally isn't as sympathetic, at least to me; if she looks 40, you just want to tell her to grow up, which I understand is the point of the character, I just find that there is a line where that stops being a vulnerable, sympathetic character trait.
Give me a bottle of bourbon and half a chicken and I'll conquer the world!