i totally agree with the others, get yourself to a travel agent, more importantly a cruise specialist, at this point to get a rapport going, get information, just so you know the shorter the cruise the harder the party crowed will be on board, and your group has families & kids, 5 day at least 7 day would be much better. A skilled travel agent will be able to get you discounts, now this could be a sticking point, who would get the discounted and free berths that will come with booking that large a group? would your family let you have it because you are doing all the planning or would they want to split the savings amongst the entire group? same thing goes for onboard credits and perks that your TA would be able to get. When dealing with large groups of friends, relatives cruising together we have found that the best way to present it is to have the ship, itinineary, cabin information and a couple of date options- and tell them is what the plan is, do you want to join us. If you leave too many options open you will never get a total agreement and you will be going round and round back and forth trying to please everyone.