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I'm glad to see you have a set dining time--that will make things easier. If you haven't done so already, ask your travel agent to cross-reference everyone's reservations and request that your dining room seating be near each other, as Dave also suggested. I don't know if requesting 3 tables for 10 would work (if there even are that many 10-tops) as they could be in different sections of the dining room. Then, when you board, make the dining room your first stop and see the maitre d' to ensure that your tables are together, or at least nearby.
I wish I could help with hotels. (I usually stay with family.) Excellent idea to go a day early. If more of your group also needs a hotel and you'd like to stay at the same one (or nearby ones), book early.