You meet two inhabitants: Zoey and Mel. Zoey tells you that Mel is a knave. Mel says, 'Neither Zoey nor I are knaves.'
You meet two inhabitants: Peggy and Zippy. Peggy tells you that 'of Zippy and I, exactly one is a knight'. Zippy tells you that only a knave would say that Peggy is a knave.
You meet two inhabitants: Sue and Zippy. Sue says that Zippy is a knave. Zippy says, 'I and Sue are knights.'