Santorini Questions!

Hello! We will be headed to Santorini on the Sun Princess next month; I've checked the cruise app, and we will be the only ship there until around 4pm when another will arrive. Half of our group is young and nimble (and not afraid of the stairs), and the other half does have mobility issues. To get to the top of Fira, I know the cable car is most direct (and longest lines). My questions:

1. How early have you heard of folks lining up for tender tickets on the ship? 5am or?

2. If you have a private tour not booked via Princess, do they let you on the tender boat that goes to the bus/driveable area?

Thank you!