Wow! You'll set a record for most value out of MM!
The site does get very cumbersome and slow to scroll through when your trip is over and you're ready to edit and download your pictures - allow yourself plenty of time before your photos begin to expire (45 days after each was taken) to give you time to deal with a slow site and still get everything done. Do a download of one set of unedited photos before adding all the borders and stickers, so that no matter what, you'll still have one clean set.
Any time your group does something like Jedi Training or Enchanted Tales With Belle, you'll receive a Photopass card that has all photos of all participants of the show on it. Do NOT load this card into your
MDE yourself. Take it to a Photopass shop (near the front of each park and st Disney a Springs) where they can quickly help you select only the photos of your own family members instead of all pictutres of all the strangers too. Entering the code yourself, you don't get the option of selecting certain ones. You'll already have so many photos because of your family size, you don't need extra shots of strangers too!
Anyone with a magic band should have their ride photos show up automatically, but anyone without a MB should stop at the photo screens at the end of rides to scan their Photopass card on their picture to capture it into your account.
You should tell family sub-groups to check the photos online periodically to make sure their photos are there. Allow a couple days, but if they don't show up there's a "report missing photos" link where you can tell them approximate day/time, location or ride, what the people are wearing and they're very good at finding missing photos. Likewise if a magic shot is missing the "magic" effects. As the organizer, there's no way you'd know what all should be there, but each family should know their own.
Remind everyone to stop at photographers often and get their MB or Photopass card scanned. Have fun!!