I invited 3 villagers from the 6-ish campers I had. I did notice however that when the personality of your next move-in has been set (even if you have 8 villagers already) that same personality will affect the campers. My town didn't have a cranky so the game spammed me with that personality until I accepted one moving in.
I was resetting for my 9th villager the other day and had Maelle, Simon, Deli, Gloria, Bonbon and Kitt in my campsite while I was searching for a plot.