JK Rowling has been pretty vocal about how she was approached by multiple people for a musical. Most notably (that we know of), was Michael Jackson. She said no to so many things in attempts to keep the Potter-verse contained, but it's funny to look back at that now with the "Wizarding World" universe/empire she's built.
It's hard for me to even imagine a Harry Potter musical, but I think someone like Florence Welch would need to do it.