This came up in the shoutbox, and I was curious about people's opinions, because I don't think I've ever seen it discussed before. If Yae had made it back to the village and performed the ritual with Sae (assuming it was successful), what do you think would have happened to her afterwards? Would she have been killed for betraying the village, or locked up like Itsuki, or left alone?
I tend to think they wouldn't kill her outright. Being the Ceremony Master's daughter and the Remaining who saved the village would probably buy her some goodwill, and I think Ryokan would have mentioned it if he only wanted her to come back so they could kill her. Whether she was free or locked up would probably depend on her behaviour, and whether she showed signs of wanting to help other twins escape, but honestly I think that, having performed the ritual successfully herself, she'd come around to her father's point of view.
I'm not sure she'd ever get as far as becoming Ceremony Master herself, though that could be quite interesting.