It is difficult to respond because I do not know enough about your family. What I can recommend is to look at some of the past navigators from a similar cruise to the one you are going on. These are the daily schedules that have all of the activities on the cruise. This will answer a lot of your questions. You can find your ship with a similar itinerary here:
http://disneycruiselineblog.com/category/cruise-planning/personal-navigators/
I am sailing in January (7 days on the Fantasy). We will not eat at the Adult Restaurants. (They are fabulous -- I have eaten there in the past). I just like the regular meals we will enjoy during our normal meal rotations. We DH (me) DW DD 12 and (my mother in law -- who is staying in an connecting cabin). My daughter absolutely loves the Muppets detective agency game (only on the Dream and Fantasy) but there are other things to do. I would print out the navigators and provide all in your family a copy to get them excited and to see what is available. First-run movies play continuously. We have difficulty making the time to ensure we see the films we want to see.
That same site will have menus for your ship on a 5 day cruise also. You can get an idea of what your meals will be like.
Another thing you can do is find a trip report from someone who is going on a 5-day cruise similar to yours. This will also give you a great idea about what to expect.
Bottom line -- plan -- ensure to fill out all of your paper work ahead of time -- ensure you have passports ahead of time -- transportation to the ship etc.
BUT don't overplan too much. That is the beauty of a cruise. You can relax.
I am an overplanner. When we go to WDW or DL I plan almost down to the minute -- LOL -- but on Disney cruises -- I plan in detail on us getting there. Once we are on board, I sit down with the family and (usually at dinner) go over the next day's navigators to decide on what everyone is going to do the next day. The only exception is if we are going to do an excursion.
I tend to wax poetical about all things Disney --so I will just leave it at that. You will have an awesome time!