Hi,

All a bit quick but ___ Welcome to the forums!

1. I don't think it makes much difference _ Zone 2 or 3 (although someone will probably disagree!).
2. You can set up using the configuration 'wizard' from the front panel (about p33 in the manual)
3. Fixed volume output (p35 in the manual) so that you can control volume from the Prime.
4. I don't think the firmware version on the G68 is an issue.

Obviously, depending on your sources you could also completely bypass the G68, and save yourself some A/D and D/A conversions.

Brian

Main: G65, MD600 Sooloos, MC200 Roon Core, MS600, 210, 218, UHD722, DSP5200SE, DSP5200HCSE, M6 & DSW.2
System 2: AC200 MS200, WiiM Pro+, M6.
Other: DSP5000 (96/24v1), DSP3300.