The only new policies that spring to mind are the new resort parking fee and the daily room inspection. The room inspection will only occur if you turn down housekeeping.
When we travel to Disney with a multi family group our planning works something like this- All of the adults get together to talk about their (and their children's) must dos. Then using any available info about hours and EMH, we plan out which park, which day, taking into consideration whether or not everyone will have the park hopper option. We pack the days with park time as well as resort and pool time. Generally we also schedule things like a trip or two to Disney Springs, mini golf, a dessert party and possibly some other extras like boat rentals or tours. Then each individual, couple, or family decides which parts of the master plan they wish to participate in and which parts they wish to break off from the larger group for. Anyone breaking away does their own planning and arrangements where applicable. Examples from our upcoming extended family trip planned for January- one day has the group spending the entire day at Hollywood Studios with a very early breakfast at Yacht Club, walking to HS, dinner at 50s Prime Time and Fantasmic ending the day. My husband and I don't like eating at 50s nor do we care to do Fantasmic, so we will leave the group mid afternoon, return to our resort for some down time then dress for an evening of cocktails and apps as we hop from one monorail resort to the next. On another day, the plan is breakfast at Garden Grill pre park opening and then a day of Epcot with the afternoon being time in World Showcase during the International Arts Festival. Some of us are not doing the breakfast at GG or the morning in Future World but will arrive in World Showcase at 11AM when it opens. We will stay late at Epcot while those who started the day in the morning head back to the resort in the early evening. Another example is that one couple has a small child who is a terror in nice restaurants so on the evenings when the group dines at Citricos, Bluezoo, and Yachtsman. That family will enjoy quick service back at the resort.
I definitely recommend that everyone have some time away from the group. I also recommend that you book enough rooms so that everyone has physical space. For the trip mentioned above we considered three cabins at Copper Creek but ultimately decided that (2) 2 Bedroom Villas, (2) 1 Bedroom Villas, and (2) standard rooms made more sense because it allows each couple or family to be in charge of their own space. Togetherness is great, but privacy makes it more enjoyable.
