We do 16-17 people trips every other year. We never get the
DDP (with or without the group). It doesn't make financial sense. We do have TiW and will use that for the one group meal we plan during the trip. That's a special dining out event we do to celebrate the trip together. The kids are all old enough to love the rides so we don't like strapping anyone down with meal reservations. Getting tables for 10+ group sizes can become hard for the restaurant to handle. It may take a little extra time to seat a group that size.
We've gotten all studios, but now we do at least one 2bedroom. That way we have kitchens and laundries. The 2bedroom acts as the "meeting place" for the group. You have a Grand Villa so you'll have a large meeting place.
We do a grocery store run (or order in) and draw up a list of all the stuff we'd need for breakfasts, snacks and meals in the room. Simple stuff like hot dogs, hamburgers, frozen food, breakfast supplies, beverages.
We pick a park for the day, but we do not attempt to tour together. We break up into smaller ad hoc groups to go on different attractions by preference.
We use cell phones to keep in touch in a park. Meet up and reform into different ad hoc groups.
We gather for specific events like parades and fireworks. Someone (usually the older crowd like grandparents who don't care to go on tons of rides) stakes out the initial viewing spot and we gather around by a certain time.
We have "pool/resort days" where we plan no park and just take over a pool to hang out in. (We rock at those resort trivia contests.)
We always stop to get a group photo at least once per trip. This is our main souvenir.
When we go to book the vacation, the point owners pick the dates and room configuration after some initial consultation with the prospective invitees on scheduling. Then they invite others to come.
The point owners also plan a night a two without the group for some decompression time. Makes it easier to enjoy being with the group if you've had time to yourself to enjoy.