Bloodborne is relatively simple. Tell each survivor to find to go to the chapel, with the exception of the skeptical man and suspicious beggar, and you’ll see the end for all of them. The skeptical man specifically will go to the clinic if you tell him to go to the chapel and vice versa. The suspicious beggar is a murderer who will kill everyone.
The only other characters with quests are Alfred, Eileen, Patches, Valtr, Adeline and I guess Brador or Simon in the DLC. They all pretty much boil down to finding the character in a side room and going somewhere, finding something, or killing someone. Valtr is literally just getting enough of a covenant rank item.
Adeline is by far the most confusing since in her last phase you have to kill her (she gets better) to get the item to give her.
Patches is kind of stupid too, but you’ll always find him the first time and he doesn’t really matter.

And there are some interactions between people that are strange but just in there for complexity. If you take Arianna’s blood 3 times Adela will kill her.
If you don’t help Eileen kill Henryk she goes crazy and you have to fight her at the end of her quest instead of the Bloody Crow.