That sounds so sweet! I would definitely be game for that. Except that it's really far along in the year... Hrm. Mayhaps we just have the auditions and people who got in and then have a small rehearsal thread.
I doubt that all people would manage to get into the chatbox to perform the play, and that would be difficult in itself anyway, so perhaps that part should just be skipped, and have the aftermath in another thread. Like "Yay, we did it". Just a little thing.