|Rubber Ducky guy|
I'm only 4 days (in game time) into my game, but I think the trust system has merrit in a way to judge the attitude of most NPCs. Just don't fall into the trap of using it across the board.
Zokar seems like he would have been interested in the professor's past adventures, and Father Grimburrow would have reapected his intelligence and experience. And then one or two other NPCs to this group and you have a few friendly individuals the PCs can bond with and use them to get the PCs invested in the town.
And on the flip side Gibs should have a few friends and they should be outright hostile for the most part
People have said that there aren't enough trust points written in the book. So look for ways to add points for good deeds and successful diplomacy. Otherwise Legendary Games has a gothic supplement with two great adventures.
If you want a villain for the players to focus on but don't want to tip AA's hand, use Vrood. Book 3 has a brief backstory for him but he was basicly baptised in death and is obsessed by it.
I made him a key figure behind the Fiddler at Dawn events from the gothic supplement which they will learn in book 2.
If the ask around about strangers prior to the professor's death, have someone matching his description visit the town with an entourage on legitimate business/cover story. Invent a stone quarry to the south of the prison he wants to reopen, or maybe he's interested in a trade deal with one of the towns many farms or orchards.
Better yet he's a representative for hsi employer, hinting at a villain beyond him.
My last piece of advice is a gift from you to the players. The professor keeps a detailed journal, and they all had a memorable encountet with him. While researching of helping put his affairs in order, let them discover his account of the adventures they shared.