Where do the "four-legged" congregate and what can I do about it?

The four-legged would be the alien dogs.

And you've already seen where they congregate.

Remember that Empty House near the Town Entrance?

It turns out it wasn't empty after all, was it?

In fact, it looked like a very busy exclusive club at one point.

You even spied on the dogs playing poker of all things from the balcony.

It's that room where they all probably spend their "time" when they're not out chasing you.

You can't go up the secret stairs in the 1600s, but remember that they exist across time.

Go to the Empty House in the Present, and use the secret passage (now open) to reach the door of that Poker Room.

It's forward, forward, right, and up the secret passage, if you tend to get lost in the dark.

That door without a knob is surely the door to the Poker Room.

It even has a doggie door at the bottom.

Intelligent alien beings they may be, but they still lack opposable thumbs.

Something heavy against an outward-swinging door should be enough as a temporary obstacle – hopefully.

Tap the bench under the window to drag it to the door.

Leave and hope it can hold them for long enough.