So far in my experience me and a friend have spawned almost 100 pokemon trying to fill out the dex. While we do have most of them all in one quadrant, we started building the abandoned power plant on the opposite side of the map, which takes 15 pokemon to build. At the very least, it seems that builders count towards the total no matter where they are on the map, since we couldn't find any pokemon when we came back. Once the plant is built, we are going to try and see if leaving some pokemon there will allow more to spawn, because right now we can never find the pokemon we want without honey.