''I truly have no idea why Olin’s spirit did not manifest in my church when I tried calling for him, and I hope this situation here explains why I haven’t remedied that.''

Says the man who’s been ignoring an entire community for years. He’s likely misunderstanding your stance; you’ve been reasonable so far, but that doesn’t mean you hold any pity for his plight: he had the power to do so much more before this strange new epidemic began.

Unity
Informing the inquisitor and involving the baron with Olin’s situation will create a nasty controversy that might just put a deadlock on everything happening in the city. Shigeko said the Mamonos have a new solution for purification; you’ll have no chance to implement it while a new bishop is being established.
If you want to bypass the mercenaries’ apparent stranglehold on the village, the church’s moral duty is the only way you can think of to do so legally.

So much to think about...

Because of Rey personality, she's a rather bad judge of character so the truths or lies of the Bishop aren't so obvious. Shigeko and Seyraphal also aren't particularly skilled at discerning lies.

>Insist on going downstairs to see for yourself this supposed ''storage''.
>You've seen enough: if Belmont is willing to start helping the monster village, then you'll promise to keep things ''reasonable'' with Olin situation.
>Return to his study to tell him about the attack on your house yesterday and what Seyraphal learned from the memories of the Risen.
>Don't make any agreements right now, you have so much to think about, so much to tell your parents...
>Free