OKW is a great resort for large groups, the rooms a large and comfortable, and the points don't break the bank. I hosted a group of 16 a few years ago in two 2-bedroom unit and a one bedroom unit. Be sure you book enough units so that individual family groups have some privacy, don;lt try to plan to do everything together...some people are late sleepers, others are early risers, and not everyone likes the same rides and attractions. Plan a couple of nice meals together at restaurants, if the budget allows. Be sure and call dining so they can book a large table or several tables nearby. For park days, basically tell folks they are on their own, but that you can meet up for a specific ride or meal if they wish. Family togetherness is great, but there CAN be too much of it, every sub-group needs some time to themselves.
Also, if you are planning to use your points for everyone, be sure to give them firm cancellation dates, and a firm date to have their park tickets for booking fastpasses. One thing everyone enjoyed as a group was the Luau at the Polynesian, we got tier 1 seats, even though they were pricey, and it was great. Everyone paid their own, of course. We did a group phone call to book dining, since the Luau is pre-paid, and gave our own credit card numbers.