Did the advice from this other thead help you complete this achievement?

https://steamcommunity.com/app/2155180/discussions/0/666115243048544886/

I am working on that achievement now and am trying out the map seed from that thread:

G6YJF1LZERZ3YVMZNVQE5CAF65QKU3AE

I still need to find the last 2 cats

Originally posted by VinniV:

This achievement is currently impossible to obtain. I've clicked through every building, every cat, and every dog. The achievement for the dogs has unlocked, but not the achievement for the cats.

There's no way to obtain it.

A couple of the official scenario maps had the last cats I needed to find in NPC buildings.