in the hunters dream, when you enter the house and then go trough another door,  you will find some bath messengers, and you have to give them 3971 blood echoes if im not wrong, i gathered the echoes, and gived them, and a message appeared saying somethink like "something is different" what does the message mean? what are does messengers for?

You're going to have to wait for another update to release

this will respawn one-time pickup items and many non-respawning enemies, afaik