Actually all the female leads are vocally easy to do:
Roesmary
Smitty
Hedy (you need some mezzo in you for one part of her song)
It's a great show! Especially for high school. As long as you have good boys. The female parts are not the best in any show, but they're fun to do. The songs are generally good/cute, and not horrible at all.
It's long but it's one of those long shows you don't mind being so long. Again though, unless you have not good boys.
Have fun!
Btw, the abbreviation for this show is H2$
I mean, Denzel Washington? Gun to my head..of course.