I think the plan should be bracing for impact, and how to deal with the after-effect. Because let's be honest, we are in a late stage capitalism, and Meta megacorp will get what it wants.

I don't currently see it spilling it's poison to Lemmy/kbin. I'm hopeful rather, but I may be misunderstanding how the fediverse works.

But for mastodon, I would say the outcome is a segregation, as it's safe to assume that communities that integrate wirh Meta will be consumed. Unfortunately that likely means starting from scratch, with a even nichier community, as far as I can see. Not exactly from nothing, but content loss will be inevitable, which is the Fediverse greatest weakness imho.