Collaborative Opera Project?

I'm in the middle of writing my third opera now, with plans for a fourth in the works.

I know I haven't been part of the thread - but the device of the pregnant sister is BIZARRE. It really comes out of nowhere. If you want to keep it, you need to introduce it right at the beginning and use it as a parallel structure to the main story. Right now, it feels like, "Oh, we need something to thematically suggest such-and-such - okay, let's stick in this pregnant sister in the middle of the second act."

A more dramatic, less thematic, choice is to have Mary-sue become pregnant, perhaps by Billy-bob? In that way you have the downfall of her family coming from her betrayal of her lover. IS the baby mentally defective? Or is she a pariah because of who the baby's father is?