Room service available 24/7. I know you will be in an "S", LadyJag, and you can have full hot breakfast for room service. (eggs, french toast, omeletes, bacon etc)
Embarkation Buffet opens about 1:30 which is when embarkation usually begins. They always have a nice display including hot soup, various salads, minute steaks, various potato offerings, often spaghetti bolognese, carved turkey, veal roast or something like it carved to order. The hamburger/hot dog bar at Lido as well as the Taco Bar in the same location.
The ZU has a cafe called ??Windsurf Cafe?? (I think--without going to get my deck plan I'm not sure) and supposedly it will have light fare and desserts, coffee etc something like 20 hours a day. I think it will only close several hours in the middle of the night.