L.K.
Well when we go with my husband's family there can be up to 20 of us. And when the kids were little, there was still a big spread in ages.
We always stay on property at Old Key West because they are like little condo's and have full kitchens. So someone always had rented a car and we went to a local grocery store and stocked up on PB&J, milk, cereal, cheese sticks etc so we did not have to always eat at the parks.
When the families had younger kids, they could always catch a bus back to the condo for nap time or down time.
There are "family pass" things (sorry my kids were always old enough) but look into them. Basically it allowed one parent to sit in a special area with a baby/toddler while the other one got to ride. Then when parent #1 got off parent #2 could get on.
Take advantage, if you can of one of the character meals. It is when you get to be up close and personal with some of the Disney Characters.
But have fun, don't sweat the small stuff and roll with the flow!
Oh, and NOT to put a damper on things. . . Disney parks are VERY safe. We knew some of the execs at one time. But I'll never forget someone telling me to remember what SHOES the kids were wearing. GOD FORBID, someone tried to kidnap they kids. . . the savvy ones will have clothes and/or cut their hair etc. But rarely will they have shoes that fit.