Ooh nice! I didn't realize how much the airport / resident services locations could vary by, that's super interesting.
You can get 3 stars with only 8 villagers! So I just never put down the last 2 plots because I wanted to minimize the number of villager houses I'd have to move around after unlocking terraforming. (And plus I wanted to save the villager hunting as a 'reward' for terraforming / decorating the island!)
I actually did just get Kiki last night and will be going villager hunting again today for my 10th villager. Moving Kiki in did get my island to 5 stars without any other changes, so I'm not sure if maybe you need at least 9 villagers to get that?