I think I've been operating right now under the assumption that, at least for the foreseeable future, even though the ao3 pilot would still be operating mainly on ao3, reshuffles and whatnot would still happen in conjunction with lj (as ao3 has no mechanics for this) and perhaps if necessary with dw later, but yeah, definitely the "headquarters" so to speak for now. If new people wanted to join the ao3 but don't have lj/dw, it's easy enough to comment anon or with other platform sign ins and just give the relevant information.