Norton 360 Everywhere/Norton One/NIS update path to NIS for Mac 5 or 6?

I am trying to sort out which Norton product to buy for my Mac (Mountain Lion (OS X 10.8.2)).  Ideally it would be a download version, a lot easier to deal with in terms of Mountain Lion, I imagine, and I do at some point hope to have Fusion + Windows 8 running also on it, so I accept that what I buy today is going to need an update or two in the near future.  But I also have some Android systems (phone+tablet), so I was looking at some of the offerings that have multiple licences.  This has led me to some questions:

 

  1. If I buy something now, does it cover me for versions (Mac, Win) that come out over the course of a year?  Or do I have to wait for the newer products (NIS Mac 6, NIS/360 for Win8) to come out?
  2. If I buy 360 Everywhere/One, multiple licenses that cover the Mac, with the additional Fusion/Win8 running under that, does that count as 1 or 2 of those licenses total (i.e. is it per box, or per instance or usage)
  3. If I buy 360 Everywhere, in order to get the license/seats, what I really need is NIS on the Fusion/Win8 instance (and lacking a NIS Everywhere variant), is it possible to subset the Win8 install to just the firewall+AV parts, essentially downgrade to NIS.  Or if that's not possible directly out of the box, could I use the 360 license to cover a NIS download?