Google has always had its own changes over what's actually vanilla on its devices. I don't see this as different yet, but that could change depending on how things go.
I'm not sure why we need to call it anything other than Android
Pure Google.
It's still Android, just with Google's improvements on top. Whether or not it's "pure" Android is open to your interpretation. Is what Google did before your idea of pure? Then yes, this is still essentially pure Android with added fixin's. Is AOSP your idea of pure Android? Then no, this is not pure Android (and Google's version on the Nexus hasn't been for a while, in that case).
For what it's worth, I consider it still to be pure Android with extra bits sprinkled on top, since Android these days is mostly what Google makes of it.
I heard that Pixel(s) have some Android features that no other phones will have... So it may be a slightly enhanced version of Android?
If the previous definition of pure Android for the Nexus devices was Android as Goggle intended then that's surely what the Pixel phone will be. OK, it's going to have some stuff no other devices will have but, as the owner of the platform, this is going to be how Google want it to be.
It is "pure" Android. Install now launcher if you want a more AOSP experience. Pixel launcher looks a lot better imho tho.