I will be watching this closely, as my boyfriend loves Audrey Hepburn movies- but I agree that there's no reason for it to NOT have an original score.
Plus (I've said this before) it bugs me that they're calling it "The Cole Porter Musical." No. KISS ME KATE is the Cole Porter musical. ANYTHING GOES is the Cole Porter musical. Hell, RED HOT AND COLE is the Cole Porter musical!
https://newplayexchange.org/users/99643/amanda-delalla