You were probably already asked this regarding your au. But would the reveal of Scratch’s human self play into your Brighton Bay AU in some way or is Scratch one hundred percent a sea beast? (I saw that one post you wrote and I can guess the ‘forget Molly’ thing would NOT show up in the AU.)
This is something I've thought about a lot, especially now after the series finale, I'm so happy you asked me this /gen
The answer to "is scratch 100% a sea beast" is both yes and no, let me explain
Sea beasts have the ability to curse humans to become sea beasts themselves (hence why Molly can become a beast whenever she touches ocean water, Geoff only half cursed her) and usually they only do it as a last ditch effort to spite beast killers (I mean why wouldn't you want to say one last "fuck you" to the person who barged into your house and stabbed you repeatedly?)
To say that Scratch killed a sea beast to get cursed is an overstatement. Perhaps I'll make a fic about that one day
I've actually been brainstorming a way to implement his past into the AU since season 2 started. Just spoilers in advance, he can't ever become human again, those curses are permanent. (This isn't even to spite The End, they'd been permanent since me and a friend decided they were a thing)
I imagine after finding out who he was, he'd reunite with Adia eventually, travel the world with her for a while, then come back for a surprise stay at Brighton for a few weeks before going on their next great adventure. Who knows, maybe they'd even bring Molly along on one?