Is there a way to scan through the presets when listening to the tuner on zone 2? There's no provision for this on the zone 2 remote, but I was hoping there's some hidden way to do this that I haven't discovered.

I'm pretty sure you need to main remote to control the tuner - in fact, I think you have to enable the tuner in the main zone to change the station (been a while since I've done it, though).