Hi Jennifer! I planned a similar trip a few years ago, and we can't wait to do it again.
Have you registered as a Magical Gathering? This allows you to make reservations for some really fun
Grand Gatherings: Safari Celebration Dinner, Good Morning Character Breakfast and Illuminations Desert Reception are all special events for parties of 8 or more. My family did the safari dinner, and we had a blast! Call (407)WDW-MAGIC (939-6244) for more information about Grand Gatherings.
Remember that it's okay to split up. Just because you're on vacation together doesn't mean you have to spend every moment with one another. What worked for our family was to start the day out together -- maybe even have a character breakfast. We'd visit a few attractions & start to split up. We would meet back together at a table service restaurant and make plans for the rest of our evening.
This may sound corny, especially if you've never done it - but wearing matching clothing helps. I'm not saying you all have to have special t-shirts made for each day of the week (although that could be fun). But, if you can coordinate the color you wear each day, it really makes spotting one another a breeze. And, an added bonus if you're a scrapbooker, you're pictures with coordinate nicely!
As far as attractions that everyone can enjoy together, my fellow Disney Mom, Whitney, has written a great answer
HERE.
If you need more help, I'd be more than happy to answer any follow up questions. Have a wonderful trip.