If I'm reading this right, it actually hosted the websites but its IP address was hidden. I don't know if each site maybe got its own IP on the host, because after all I'd think it would be trivial for a customer to upload some code to unmask the host's actual IP. https://web.archive.org/web/20170830191551/https://hosting.d...

If the .onion host is competent, they use iptables to restrict output to the Tor process.

No, by "hosting" they mean shared hosting, with multiple .onion sites on one physical server.

Each of those .onion sites would have its own Tor entry guard relays, and would negotiate its own rendezvous points. An .onion service, just like a Tor user, selects a few entry guards that it uses consistently. And gradually replaces with new ones, over some weeks. But rendezvous points get picked fresh for each client-server connection.