The standard DDP is a nice option for keeping things simple when traveling with a larger party, and the pre-planning aspect for TS meals can actually help by preventing situations where everyone is standing around going, "what do you want to do? I don't know, what do YOU want to do?". You are unlikely to save much money (though with good planning you can at least break even), but the simplicity is worth it when you have a big, diverse bunch of people.
Here's what I'd recommend (such advice is highly individualized, so you'll have to take it with a grain of salt). Planning your dining really has to dovetail with your touring itinerary planning.:
1 - You have several months to plan. Designate yourself as the official table-service meal planner and touring itinerary maker. Have a little family meeting to educate your traveling party about some restaurant and touring options (or watch the WDW planning DVD and distribute an information sheet and survey for both dining and attractions -- I know it sounds like overkill, but I did this and it really, really helped!). Find out and write down everyone's food allergies and aversions, favorite cuisine type, etc., and who-can-do-what in terms of attractions If they have any "must-do" restaurants or activities, this is the time for them to speak up or forever hold their peace. See how they feel about character meals and/or meet-and-greets. If they're going to have one "big" meal per day, do they prefer a leisurely breakfast, a lunch or a dinner? Which park(s) interest them the most? (Keep in mind that you'll maximize the value of your TS credits by focusing on expensive venues at dinnertime, and by avoiding 2-credit restaurants and dinner shows unless you want to pay for them out of pocket.)
2 - Once you have that information, make a list of the best restaurant choices for your party. If they want variety, try not to visit more than one restaurant that serves the same kind of cuisine, or do more than one character meal with the same characters. Once you have the restaurants chosen, make out a rough draft of your touring itinerary (e.g., AK on Monday morning, Epcot's Future World on Monday afternoon) so you know which park you'll most likely visit during the morning and evening each day. See if you can match your ADRs to the parks you intend to visit. Then list the date, restaurant, and ideal time you want so you can use it as a reference when you make your ADRs. For popular restaurants, include a back-up restaurant you can book if your chosen restaurant is full. (e.g., 'Ohana with Kona Cafe as a back-up at 6:00pm on your last full day, when you plan to visit the MK, etc.) If you wish, double-check the menus for those restaurants to ensure that they offer a standard Americanized kids' menu (so many of them do that you can probably skip this step). Unless you plan to visit Victoria & Albert's, small children (especially if they're well rested from a midday nap) are welcome everywhere! Restaurants offer colorful (and color-able) kids' menu placemats that help to keep the kids' entertained, and you may be surprised at how well the kids do at a sit-down restaurant. (If you don't think they will and really only want a couple of sit-down experiences, burn those credits with 2-credit kid-friendly experiences like dinner with the princesses at Cinderella's Royal Table and a boisterous dinner show like the Hoop-de-Doo Musical Revue, and pay out of pocket for additional counter service meals.)
3 - 180 days out from your arrival date, make your ADRs online at 6am. (Start with the most popular options you want, and then get to the easier-to-make ADRs later.. That means Cinderella's Royal Table before Biergarten, Hoop-de-Doo before Whispering Canyon). If and when you get a pop-up screen allowing you to add food allergies, do so if there are any for the people in your party. WDW is GREAT about working around them, and will typically send a chef to your table to tell the persons with allergies what they can/can't have from the menu, and what dishes can be modified to accommodate them.
4 - Once the ADRs are made, circulate a draft itinerary (with the ADRs) to everyone in the group, emphasizing that except for times where the group has an ADR, they are free to depart from it at will. For a group with small children, I really recommend: (a) mornings that are relatively unscheduled with everyone on their own for breakfast, and a park designated for the "ropedrop early risers" at which "late sleepers" can later join them for a CS lunch at the CS place of their choice, or go off somewhere else if they prefer; (b) an unscheduled period from 1pm-4pm, during which those with small children can return to the resort for naps or swimming; and (c) a 4pm-bedtime park, at or near which the whole group is expected to meet up for a dinner ADR. Encourage the parents of small children to get them to bed around their regular bedtime every night except the last one. (This is a great way to prevent any meltdowns.) Obviously, to allow everyone sufficient flexibility, you'd need parkhopper tickets to make this work. You also should take into account the likely extra magic hours schedule for your travel dates. If you want to make use of EMH for rope drop, I suggest hopping to a different park later (as EMH parks will have higher crowds all day). Conversely, if you want to do evening EMH, hop to the EMH park in the evening from another, non-EMH park.
Time is valuable at WDW and pre-planning is the key to survival.
