Also beware of what ordnance you have. In my case on my spare town, I did not have beautiful ordnance. This meant that I had to leave random spots open to allow weeds to spawn, along with the breakable rock. there did have to be multiple spots left (not just the required).
What did happen to me, is that when I left just the space available that I wanted, I had weeds appear there, which then let the villager spawn to a random (and of course inconvenient) spot.
And another gotcha, if you harvest fossils, then you need to leave spaces for them to appear also - this is why it is best to leave fossils + pitfall buried (and do not break the unbreakable rock) so that they do not throw off the space you want the villager to appear.
Ah, I wasn't completely aware of that. I have the beautiful ordinance, so I don't have to worry about weeds. But I do have bamboo grow on a space, and eventually had a villager move to a different space I had made. So, that's also true. I'll update the guide w/ that
Thank you!