Dream Zoo Adding Visitors as Neighbors

I'm not sure if this is a new feature or not, but as  Baskerville Hounds commented on one of my post, (s)he was able to easily add visitors as neighbors when s(he) visited them. I have also confirmed this. When I go to a community zoo who has visited me first (you can tell because they have the "Revently Visited" tag on the friends window), there was be a popup at the top of the screen asking me if I want to add that community zoo as a neighbor.

Speaking of which, I'm really curious as to what the cooldown of the new community zoo friends are. I try to go to the Dream Zoo of the "Other zoo players" at the end of the friends list, these are the people you are not neighbors with but the game has shown to you so you can visit them. I definitely know that if you visit them all, they will reset in a few hours, but I want to know the exact-ish cooldown timer. Too bad I'm not always able to get to the game, so I have to try after few hours when I get the chance.