One thing that worries me is the Taoist and the village itself. Okay, we were supposed to find a village but didn't find it, we have no recollection of how we got to the village OR the mansion, or how long it took to get there. Also, thunderstorm strikes just before the monk comes, and now, just as we wake up in the ghost house? This stinks. This stinks of shenanigans. I'm almost glad that we voted A to come here now, for all we know we already met the ghost last update and gotten trapped in its illusion - maybe we wouldn't even have made it to Xiangyang and just gone around and around in circles or something.
The one important clue we have here is the melody - it's familiar, something that we've heard since before coming to the palace. And hmm... not too long ago, treave let slip that we have siblings...
...IMOUTO-CHAN, IS THAT YOU?!
Hah. Figures that Codex would go down the incest route.
That aside, it's obvious that the girl wants us to engage in some way (blowing out the lights, making it so that the door on the left looks warm and inviting), so what's going to happen if we DON'T engage? Is she going to chase after us? Will we just be led back to this room again? Will she switch her focus to Xiahou Yu instead? IS Xiahou Yu already in there with her? I assume not, seeing that our Reikan didn't detect anything. If Esquilax's theory that the Taoist is using us as bait to be true, the Taoist would expect us to do either A (because horny young man) or B (because gentlemanly young man), so do we WANT to go along with that to help the Taoist out? Another possibility to consider is that the exorcist IS the ghost here and the girl within is a victim that the exorcist wants us to think is a ghost or maybe I'm being way too paranoid here but seriously the whole "not being able to remember how we got here" is giving me the fucking creeps.
Also, horses. HORSES. FOUR MEANS DEATH WE'RE ALL GOING TO DIE. Omens aside, does that hint that this is some kind of mundane prank, because why would ghosts need horses? Is this who situation something that this Taoist has set up to perpetuate rumours of his capabilities as an exorcist? Was the so-called village leader a confederate? In which case C might lead us to uncover the mechanisms behind all this. Do the horses belong to the stagehands involved in setting this up? Then again, Yu described the bedroom as dusty, like no one's been there in a while. I assume that means he saw no footprints or such there? Which you'd expect if someone had physically carried him there.
So going under the assumption that this is a supernatural situation, what is the significance of the horses? ...they're horse demons? Wait, if Jing's imouto-chan is a horse... does that mean that he's a horse too?! Wait no, we're a Tiger that makes no sense whatsoever! *may or may not be going slightly crazy with all this speculation*