Hayley Anne
Skye Louise
Alexandra May (Love it!)
The boy names are all names I like, but they don't seem to fit the pattern you've set. If I were playing the game, "Which one of these things doesn't belong," I'd say that the name to choose is Phoenix. Can't say I like the name, but it sounds like it belongs in a family with Hayley and Skye. Ian, Logan, Owen, Julian, Sebastian, Brennan, and Vaughn are the types of names I'd expect to see with sisters named Hayley Anne and Skye Louise. I think my favorites from that list for you would be Owen and Logan.
Owen Morgan and Owen Grant both sound nice. Logan James and Logan Carter both sound nice, too.
Hayley Anne, Skye Louise, Alexandra May, and Logan Carter sound like a family!