No this is people who have registered john.johnson.name, but johnson.name remains Verisign's (and e.g. unrelated Alice has also registered alice.johnson.name)
Which is an insane scheme to begin with. Why not "john-johnson.name"?
So that you could use john@johnson.name as your email instead of john@john-johnson.name. The .name gtld was created in the height of the "we will move to a paperless world and email will become the universal way to communicate" era.
I just own lastname.com so my email is first@last.com, would recommend (I guess probably a bit harder nowadays)
Only one person with a given lastname can do that (or I suppose one person and their near family).
Because registration of second level domains in .name was not available.
I don't think so. If you own it, you can have any subdomain.
At least I hope this is the case. I have a memorial page for my uncle under hisfirstname.ourlastname.name