I was hoping someone from Symantec might have replied by now, maybe they can answer officially. There has been a bit of talk on the forums that 7.0.6 will fully support Windows 7, including PBA, authenticheck, SSO.
In terms of the upgrade, nothing will change when you upgrade the management servers, but when you create the new 7.0.6 client packages you will set everything up as you want (e.g. with pre-boot, SSO) and then install it, the installation settings will apply and as long as your AD policy doesnt conflict, I would think it would work as you want. All this is just going on how previous versions have worked obviously, it could well be different next time around!
There are some reports of 7.0.4 still working on Win7 - maybe you could skip 7.0.5 and go for 7.0.6? I dont think you'll have to wait that long. Drop Symantec support a line to ask about the release date