I’ve used bluesky, and it’s very twitter-like. That doesn’t seem like the best model for a close-knit community. For larger ones, perhaps!

There are projects that make running independent atproto networks "easy": https://github.com/verdverm/testnet

I no longer recommend ATProto, in part because the public by default was a terrible choice. People prefer privacy, not anyone in the world able to read all of their activity. Bolting permissioned buckets on after the fact is not the way, it needs to be core to the protocol design.