I have a new villager moving in, today the fence outline is there, tomorrow they will move in. Does that mean tomorrow also a new neighbor outline will appear or the day after when the previous neighbor is fully moved in?
Im assuming you have a smaller amount of villagers, for example at the start of the game villager A will 'officially move in on the 17th (meaning their house is built, but still boxes), a plot will normally appear on the 20th, a couple days after, and villager B will officially move in on the 21st.
I dont have much evidence for this but what happened at the start of my game
If this new villager that is moving in tomorrow is your 9th villager, a 10th wont appear by itself, you need to get your 10th by convincing someone from another town to move in or from the capsite