How do I get a villager to move out?
You ignore them for a week or more. It can be a lengthy process and the most successful solution right now is to time travel back 15 days, interact with the villagers except for that one villager you want to leave then come back to the present. Then, watch for the villager you want to move to appear "in thought." Interacting with them at this point has the chance for them to ask you whether or not they should move.