if we are talking about P2P DNS only, it is more like "namecoin". Tor do not have anything like DNS. You can have local directory, but it is more like /etc/hosts

Yes it does. It's called "Hidden Service" and you get a *.onion address ( https://www.torproject.org/docs/tor-hidden-service.html.en )

Although you cannot control what DNS name is given, so it's not a full DNS drop in.

this is not really a name, it is generated key/address/whatever. namecoin allow you to choose name, where in hidden service subsystem you can generate one (although, you probably can setup key generator to get desired name... like vanity bitcoin addresses..)

Tor does the anonymous routing, and the distributed DNS (with *.onion domain names). However servers still have to be physically located in one place.

Freenet IIRC does the distrbuted hosting.