I'm going on Liberty in September with also 10 family members. MY suggestions would be to pre-book any excursions that you really want to do. I understand that sometimes they are cheaper when you get ashore and buy the trip locally, but I fear being left on the island should a local trip be late returning to the ship. If it's done through the cruise line, the ship will not leave you behind. I also like to book any special meals at Chopps or Portfinos before getting to the ship. I don't know how much soda the kids will drink, but it will probably be about $45 per kid for the week, and no, they cannot use the others card to cut costs. They'll each get a small drink cup to use and just present their sea pass card with the drink stamp on it, and they'll get some soda.I believe theather shows and the ice show tickets can be received on board (no costs).
We plan on arriving at the ship around 11-that time has been good in the past on our other cruises on Mariner. Boarding goes kinda fast, so plan on lunch on the ship at Windjammer, and have a great time!