So you know Ellie. She loves her sister and is so glad she's here!
I think she and Alek could get along! Until recently he's just been moving around a lot, working odd jobs and trying (and failing) to be a writer. He has not put on his big boy job pants, but he's just come back to Maine and is going to seriously work more on his writing and stuff here! We could say he and Emsley have crossed paths before or have them just meeting, but either way I think they are somewhat similar.
Juliet also has that adventurous streak to her, so I could see them become sailing buddies or whatever and doing some fun adventures together!