So Republicans have ODD?

I agree; this is a very powerful feature of Liftoff that I haven't seen in other apps.

The ability to synchronize settings such as block lists and subscriptions between accounts would be most welcome as well.

Are there really any options other than minio?

I skimmed the article and I still don't know what this clickbait solution is.

But that's not what this conversation is about.

It would be the mod/admin who moves a community to a new instance, and the users would migrate themselves to follow the community.

Neither functionality exists but I agree that users should not be moved automatically unless it's part of an SSO scenario.

Have a look at lemmit.online for someone doing something similar for Reddit content.

Also make sure your bot self-identifies as a bot, so that those who don't want to see any bots can avoid it.

Make sure you enable the "Bot Account" option in Settings:

How about a Mirror option which goes deeper than just federation and allows communities to cooperate on designating a Primary and Secondary replica, and promoting a replica to Primary (thus demoting the old Primary to Secondary) would require mods on both sides to cooperate...

I might have made some of that up but thank you for catching the intent of it.

Liftoff (Android) has an option to show All from multiple signed on accounts simultaneously. That might be worth checking out.

It's under active development of course and I did find it in Google Play after searching by name ("Liftoff") and scrolling down.