I think maybe the best action is to draw up plans for a new instance, in public on here. That way, if Tom returns, the plans can be used to continue/help this instance.

That's my thinking - I posted about it somewhere else in this thread.

If we can get volunteers to admin, then Tom only has to swoop in, promote them and we'll get refederated.

If the worst happens, we have admins in place to migrate to a new instance.

It might be worth having a discord/mailing list or similar, not for the planning, but to give a location for discussions to happen if the instance vanished suddenly.

I started a feddit.uk Matrix space. It's handy to have in case the server goes down for whatever reason (lemmy.world started their Discord server because of all the DDoS attacks and now have a Matrix space).