Disclaimer: I might be talking out of my ass here but this is how I think it works, to the best of my knowledge.
The safest way would be to make an instance that only hosts the communities; it has no users and therefore federates no subscriptions of other communities who’s content you may need to police for stuff like CSAM that isn’t caught right away. You’d only need to monitor and moderate your own communities created on the instance.
I’m not sure but you might need one account to be an admin/ moderator for the communities you create? Just don’t subscribe to any off-instance communities with it and it shouldn’t federate those posts.
Folks on other communities will interact with it via someone from their instance subscribing to it; so discoverability might present an issue.









You forgot “radical left communist liberal”