Hi.
If your party includes all adults, then I would go with late dining. This being as group event, find out, by calling Disney, if you can arrange a cocktail hour for your group, Palo reservation, etc..
Also, if you all manage to stay in the same hotel, assuming you're flying down the night before, all chip in and rent a bus to take you to the port! $20 a head should get you somthing!
I had no problem doing laundry on the ship. As a matter of fact, next year I am bring more detergent and less clothing! Don't forget your dryer sheets and quarters! I did laundry very late at night and found it peaceful and quiet.
My biggest mistake was bringing my laptop ( I never used it) and bring too many shoes. I ended up wearing my Keds, white sandals and black slingbacks. I brought 7 or 8 pairs! What a waste of space!
As far as group activities, I would arrange for one or two-max, get togethers onboard. IMHO, trying to plan everyone's cruise will backfire on you. Let each make their own shore excursions reservations.
Many people stress the importance of a carryon bag. Bring less than people suggest. I suggest any daily meds you take, in their prescription bottles, a pain/fever reliever, an antihistamine and motion sickness meds. Please do not do what I did and clear out Duane Reade in preparation for your trip. It is a waste of money and time. A bathing suit, if you plan to swim on embarkation day (I didn't). A good book- (I love to read).
Important packing tip. Do not pack your cruise documents in your checked luggage. They belong in your carryon bag.
Gosh- I have turned into such a windbag!!!
Good Luck
Ursula