Good questions (and answers!)
As far as rocking, in normal seas, I do not even know we are not on land. In heavy seas, for me it gets a bit interesting, but is more fun than sickening.
For my wife, she will feel a bit queasy the first few days and be fine after that regardless of the seas.
In short, it only depends on how susceptible you are to motion sickness as well as the size of the ship.
I usually like to sail as high up and as far forward as possible, and except in heavy seas, there is little motion. If you are on a lower deck in the middle, then there would be virtually no motion.
On a large ship, there is about 99% less motion than there would be on the lifeboat, which are larger than normal size motorboats that you may see at the local lake or in someone's driveway.
Regardless of what kind of food you do like or don't like, you will definitely not go hungry. There is something for everybody.
As far as safety, I would parallel OldGrayWolf's statement -- although I would liken it to a small town rather than a city.
Have fun on the Oasis of the Seas in the Western Caribbean in November. I am sure you will have a great time.