Someone sent me a private message that he or she thought "Sorry Wrong Number" would work very well, especially with a Sondheim score.
My objection to "Sorry Wrong Number" is that it's too short, and requires padding to become a full-length musical. (Remember the movie?) However, I think it would be great as a one act mini-musical, with the other act being another mini-musical (musicalette?) thriller or mystery story done humorously -- an Agatha Christie Hercules Poirot story perhaps.
Actually, isn't "Sorry Wrong Number" what the angry Les Miz cast members yelled at Ramin Karimloo when, instead of Bring Him Home, he sang Music of the Night one evening?
Audrey, the Phantom Phanatic, who nonetheless would rather be Jean Valjean, who knew how to make lemonade out of lemons.