When you apply for Alpha/beta, you do it at the SE account level, not the ffxiv service account level. Since the whole family plays, we'd all like to be able to participate in the beta.

With multiple xiv srevice accounts you can log in to multiple ffxiv characters at once, but they're billed seperately, so for one SE account i was paying just over $60 for 4 xiv accounts and 2 xi accounts.