in my experience, they tend to like plotting where the old villager was, but as long as there's another valid 3x3 spot, eventually they will move there. you're not stuck forever with the same placement
Their houses are that small, thought it was 4x4 oh well, TIL. ty.
But yeah if you are booting people with cards or amiibos, you can always plot around the houses and they shouldn't take that place again. Worked when I did it, but yeah always make sure to path your town or just plot reset.