I can't believe they're actually talking about "Tarzan" - sorry, but that is one of my least favorite Disney movies, and it is NOT a musical!
They should absolutely do Hunchback - and they should take advantage of the opportunity to improve on the movie; for a start, either drop or radically rethink the Gargoyles. I'd rather keep a happy ending, don't do the "kill everyone off" thing, but don't be afraid of the darkness, emotion, etc. I'm biased, because I'm a big HoND fan from way back, and it was the HoND fandom that dragged me into my netlife, but this is absolutely tailor-made for a big stage production.
"In my own little corner..."