By "full", I mean that it can do DNS. Windows not supporting RDNSS doesn't mean that you have to set the server manually; you can set it automatically.
Yes, full. Only on limited scenarios (not the most common ones, BTW).
I'm not really a fan of RDNSS; it puts host config into RAs with no clear guidelines as to which config options ought to be in them. (Why do we only put DNS info in there, and not all the other things you can configure?)
These are all the usual network settings. Sure, there's edge cases, but the idea is to cover the basics.
But I'm not arguing that MS shouldn't support it, I'm just pointing out that Windows isn't so incapable that it has no way of setting DNS servers automatically.
(As an aside, Windows will also configure a default set of DNS servers if you have no other v6 servers configured, so if you're doing a v6-only network and you really don't want to run stateless DHCPv6 for some reason and the only thing you wanted to set was the DNS servers, you could just add fec0:0:0:ffff::{1,2,3} to your DNS server and Windows would work fine.)
That's a microsoft-only made-up standard. Not only that, but using that address space was deprecated in 2004, so implementeing is actually incompliant.