Hi there! I'm sure you'll see a huge difference between your all-inclusive in Aruba and an Olivia trip. You'll never want to travel any other way!
Typical drink prices can vary. Usually the daily special is around $5, but the prices can increase a LOT from there. I'm not sure how much beer is on the cruises. I'm really not much of a beer drinker so someone else will have to field that one.
The spa services on the Holland American cruises are quite good. Got to admit, I prefer the spa treatments at the Club Med Resorts, but I have gotten some great massages on the cruises.
Yes, there are some activities scheduled late. But you will find that there are more "early" than "late" people. Or at least that has been our experience.
SOME people do get seasick on cruises. The conditions of the sea have a great deal to do with it. Most people who do get sick on a small boat generally don't have many problems on the bigger ships. The bigger the ship, the less you feel it move. Also, if you are prone to seasickness, stay to the lower levels of the ship. The higher above the water-line you go, the more you will feel it sway.
Hope this helps!
Deja