On the topic of reply gating.
Since Mastodon doesn't support it out of the box, I had added these settings under 'User Safety' a while back.
There are far too many people who think they're entitled to be able to reply to anything posted on the Internet, and there's far too much harassment that hides in the folds of federation.
Hopefully these types of User Safety settings will be adopted upstream sooner than later, allowing communities to grow.