"1: These could deliver into my apartment on the nth floor by coming through an open window, as well as the mentioned balconies and front yards or the roof."

This is what I would like. Even if they use a regular delivery truck most of the way, it would be great if they could cover the last fifty feet with a drone, to leave the package on my balcony.

(Amazon's switched to using their own courier service in my area. They make one delivery attempt only and won't leave packages at the door. So right now I can't use Amazon any more.)

Technically, this seems really hard, since GPS might not be enough---too much interference close to the building, trees. But maybe it is possible to get enough onboard visual processing to make it doable. Pretty interesting research problem.