I understand that Mastodon has a "local feed", and even if you're its sole user, if you don't block anonymous readers from access, that means someone could technically see a message by someone else that you're subscribed to, take umbrage at it, and sue you for making it available on your server, even temporarily.
From what I've seen of Mastodon, it does seem possible to block access to the server's local feed, but I don't know that for sure.
In addition to the local feed, there's also what you personally boost. I'm not sure how one strikes a balance, and if the software is still usable, if you were to hide the main URL for your feed (at least, the URL so that visitors from the web can read your feed on your server). Would it still be possible to participate in conversations, would people still be able to subscribe to you?