Evie would have said hi to all of them, and she definitely made sure that Molly and Hazel had their swimsuits in time for the party. She is also perfectly fine if Cleo wants to mermaid out.
Courtney would have gone swimming with Molly, and been excited to meet Rufus. She's never met a telepathic cat before, so she thinks he's super cool.
Ocacho would have hung out with Cleo and gone swimming with her.