I want to move my communities to piefed.social but the original instance is dead: how does that work?

I have two communities on SDF and I'd like to move them to Piefed. But the SDF instance is dead.

I've been meaning to do that for months because the SDF instance has always worked like crap - when it worked at all - but I put off doing it because it was still kinda sorta working. In fact I specifically joined Piefed for the purpose of exfiltrating my communities from that godforsaken instance.

Well, I waited too long and now the SDF instance is properly dead. Despite the message on the main page, knowing SDF, I'm pretty sure it'll stay dead forever - or at least for a very long time.

How can I move my communities here? The instructions say I should lock the communities on the old instance, post pre-migration notices there, submit the move requests here, then post final migrations notice on the old instance. But of course, I can't do that since the old instance is hosed.

Can I submit a move request for my communities and lock them / post the migration notices later on the SDF instance when it comes back online (if it ever does)?