Carrie and Benny took English names when they moved to the surface, if you wondered. And no, Avery didn’t initiate it.
-EDIT- Apologies, I meant to include this as a reminder link last night and it slipped out of my brain. Here is the beginning of the sequence where Pohl describes how the civil war got started.
Selkie: I cans marries a humans?! This changes everythings...
Todd (grinning jokingly): Hmm? Got your eye on someone, do you?
Selkie (pausing for a moment before answering): ...Yeahs. James Bond.
Avery: Wow. Really?
Selkie (smug/decisive): Hes wills be mines. I'll tames hims.
Todd: Well good luck with that one, hun.