Cheers Pete,
Of course, the AP will follow the FD.
Regarding point 2, yes, I should have mentioned that I'd need to select V/S. But if I chose to drop out of VNAV with the AP connected and a different ALT on the ATL SEL, would the MCD default to ALT HOLD or......?
Are there any advantages/disadvantages to FL CH vs V/S when changing ALT? I guess that FL CH may provide more info to the FMC for trip calculations.