Hezzie....
#1 Lifeboat drill is at 4 pm and lasts 30 minutes, or less, if everyone gets there promptly at 4.
# 2 Disney cruisers seem to prefer early seating, likely because they are more likely to have younger children. So it is harder to get on Disney. On other lines late seating seems to be the preferred time to eat. There is no question that Disney is an "early to bed, early to rise" cruise as compared to other lines. Late seating tends to be more relaxed, you have time to get ready on port days. HOWEVER, Disney does something other lines don't....if you have late seating dinner, your evening show is BEFORE dinner, which kind of defeats the reason a lot of us prefer late seating. Now for some shows, they do put on a third show, after late seating dinner. So late diners can skip their scheduled 6:30 pm show, and go at 10:30 instead, or go to the 6:30 show and see the show a second time at 10:30.. Early seating shows are at 8:30 pm. This also gives early seating folks an option to skip their show, and go at 10:30, or to see the show twice. On a sea day for one show they did an afternoon showing instead of the 10:30, at 2 pm.
3) Can't answer. Had no interest in Spa, Palo, and our kids weren't interested in the clubs.
4) Should be able to wander around without an excursion no problem...mind you I haven't been to Nassau in 17 years, so don't know if things have changed or how Disney handles things.