I just had surgery recently, so I won't try to answer most of your questions. However, I have been on several cruises. A cruise ship is the LAST place I would be worried about getting suitable to eat. If you eat in the dining room, special requests can always be had. When you made your reservations, be sure your travel agent pre-alerts the cruise company that you'll have special dietary needs. If you plan on eating in the dining room often (it's my fave), be sure to speak to the maitre-de (sp?) on the first day of the cruise. This will make your special requests go much, much smoother. On my last cruise, a lady at my table had some really strange food requests due to some type of health problem. The waiter always brought her exactly what she wanted. Also, I noticed the maitre-d came over to our table every couple of nights, and asked her if everything was satisfactory. I've only cruised on Royal Caribbean, but every night, in addition to the entrees that change around, they always have another set menu that includes salmon, steak, grilled chicken, etc. Also, if you pre-arrange it with the maitre-de, you can get a shrimp cocktail appetizer every night if you want...instead of just the 1 or 2 nights it is normally served. Shrimp should definitely be easily digestable.
If you choose to eat in the buffet restaurant, there are lots and lots of choices...some appropriate, some not. For breakfast, the Royal Caribbean ships (and probably others too) always have an egg station set up. There are 1 or 2 cooks who will make you a fresh omelet to order, or make the eggs (or egg beaters) anyway you like. The food choices for lunch and dinner are numerous, and you will definitely find something appropriate.
My only concern would be eating on the days the ship is at port, and you are out and about. Depending on where your cruise is taking you, it could be difficult to find something appropriate to eat. (I haven't taken a cruise since before my surgery, but I have eaten some really odd things in foreign countries...not sure if I'd want to do that now that I've had the surgery.) I would suggest taking some individual packets of protein mix that can be easily mixed to a bottle of water. (Nectar Syntrax fruit flavors taste great mixed with water.) Or, if you can handle beef jerky at this point, it is a great source of protein. Whatever you choose to take off the ship, just make sure it is pre-packaged...the different countries/islands have some very stringent rules on bringing food into their countries, because of contamination/insect issues.
If you want some really excellent advice on the cruise ship aspect for the particular company you are cruising with, try posting this question on the message boards on CruiseCritic.com.
Oh, and congrats on your upcoming wedding!
