Okay, I've listened now, and if there are hints, I'm missing them too. The Rabbit who is talking to Cleric Chih has a burn on her arm, and I kept expecting that to prove something, but I don't remember any fires happening. And the way she talks about In-yo makes me think they can't have swapped towards the end of their story, because she wouldn't talk about herself like that, you know? And before that, In-yo was doing all that northern espionage that presumably Rabbit couldn't have done. And In-yo seemed so ambitious; would she give up the throne?

Otoh, the Rabbit talking to Cleric Chih keeps saying, "Do you understand?" and there's one point towards the end where In-yo says that too, so... but I don't know if that means anything.

I always thought it was just the story of Rabbit giving her baby to In-yo to be the future Empress. Hm, maybe I need to read it in text instead of listening in audio.