Lend the teacher a copy of the cast recording and ask her opinion of it. When you've got a conversation going, show her Scott Miller's book. Ask her to read the chapter on Assassins or Merrily or whatever. The book is practically a blueprint of everything the teacher needs to know about the show. It could even be used as a teaching guide for classroom discussion of the production.
Teacher saves face, kids get to do a show they want to do.
You've eaten all my cheesecake. Merrily We Roll Along, Les Miserables, My Fair Lady, Pippin, Sweeney Todd, and West Side Story , is required reading for anyone planning a production of any of these shows. Passion is logistically easy, it's just that the characters and relationships are extremely complicated. I'd love to pass them my Passion chapter to give them a head start.