Returning to tenants of Yharnam (first section)

Once you complete certain parts of BB, return to some of the tenants of Yharnam and they'll give you different responses (instead of f--k off) and/or items. Example, I visited the infinite coughing guy in Yharnam (first spawn location) after beating Paarl. Coughing Guy gave me new info and a mysterious object that I do not know how to use yet. Also talked to the prostitute tenant and told her about the Cathedral. She showed up later.