Cameron... in order of preference: Petri, Penelope, Chico, Candi or Greta

For Petri, go to the Twitch channel for sakuraaagaming and find the code for the island named "Quinn". Just go to Petri's house, and ask her to move to your island. I wasn't able to find treasure islands that have Penelope, Candi, or Greta. Also - Chico was not included in ACNH.