I wonder why he needs the love potion if every chick in that town is horny for him, could it be to break the rich woman
Seems like Emily needs it to impress her father.
He'll have some use for it too: probably the rich woman as you say, but my guess it's the nun has something to do with it too.
The nun is one of the connections with "Lust epidemic", together with the ghost as well as the tresure its self.
I'm very curious too to see how it plays out. I "sense" the potion story is more ancient than the game stories them self, and perhaps Valery and Bred fucking on the beach wasn't just a cameo.
All in all my feeling is the potion is more a "character" in the plot rather than just an item.