Julie - I believe when you book a package that everyone on the package has to have the same things - the same # of nights at the resort, the same # of days on the tickets, and everyone has to either have (or not have)
free dining.
So, I believe that if you get an AP, you will need to rebook (or change, however best works) everyone in your family to having one-day base MYW tickets, still with the free dining. (I know the dining credits are based on the # of nights you're staying - they don't have anything to do with the tickets.)
Then, when you check-in to your resort, you can let the CM know that you would like to upgrade the other 3 members of your families 1-day base tickets to tickets for your length of stay (however many days/features you need). As Chanon said, you will still have YOUR 1-day base ticket. You can put it away to use later, or you know, you might even be able to apply the worth of your 1-day base tickets to the $$ balance of upgrading everyone else's tickets. (I'm not sure about that part, but don't see why you couldn't. Although since 1-day tickets are more expensive per day than the other higher-days tickets, it might be best to keep it for use down the road, or to apply to tickets another time.)
I hope this helps, and didn't confuse you more!