Thanks for the guidance. I was using the Kodiak with the G1000 NXi and AAU1 and you are right that LPV specifcally does not does not seem to be modelled yet (as you describe).
When Transitioning from NAV+VNAV Mode to Appr Mode and you have the GP captured, VNAV Turns off and the AP goes into GPS+GP mode which is really what I expected.
I will have to try out an LPV appr (if its available) to see what the NXi does.