We used drivers from Welcome Pickups for port-hotel and hotel-airport transfers last summer while we were in Athens, and discovered they do pre-arranged tours to explore an area. You might get that app and check it out.
a) They'll seat however you prefer.
b) Either---never had to wait more than 15ish minutes.
c) Wife liked the space on Apex.
d) Time you choose is irrelevant---it's administrative. Reservations not required.
And the arbitrary line draws steadily closer for me (68) as I decide if I should do the Philadelphia marathon, or just opt for the half. (I was the 1st up and back down on our hiking excursion to Norway's Pulpit Rock on our May cruise)
2) Passengers are not tested unless they present themselves as ill.
4) The only dining on Magic Carpet is Chef's Table. Otherwise it's a bar (unless tendering).