Hey there
> Can there be multiple communities with the same name?
Sort of. Communities are "namespaced" to the pubkey of the person who founded them. So for example, there is not a single, global n/. Rather, I can start a community like n// and you can start another community like n/AI/. This allows competition among moderators and prevents people from squatting valuable names (unlike reddit where the first person to register a name owns that name globally, forever).
> Is there a way to change the community "metadata" (name, logo, description, rules, mods) after creation?
Yes. On https://satellite.earth, you'll see a list of all the communities that you've founded or are a moderator of in the 'Communities' section when signed in. If you click 'Settings' next to one of your communities it will bring up a form where you can edit its metadata.
> Anyone building a way to check the size and health of each community (number of followers, number of posts)?
I'm working on that right now actually! (assume others are as well)