First question, many people set up their IRC client so that other users cannot see their IP. Obviously you can't hide it completely or you would not be able to interact with the IRC server.
Second question, YT was wrong. Only mods and admins can see those details.
As for #44 and #45, I'd prefer not to sit teaching you to use twenty year old network tools - it's gone one in the morning here.
I suggest you learn about network structure and DNS, it will answer all of your questions.