Hey There GeneralTso! I booked a VIP Tour experience that was similar to your circumstances this apst August; we had 8 adults, and one teenager in our party, started off at Animal Kingdom Lodge - Jambo House, and did close to your 7 hours, with 8 hours total with our guide. If you want to see how it went down, please take a look at my post in another thread at the following link:
https://www.disboards.com/threads/has-anyone-done-a-private-tour-of-disney.3701285/#post-59636939
As you'll read in my post, we were able to visit all 4 parks on a hot August day. When you consider the fact that most of the the set-itinerary VIP tours are close to $300/person, the bigger your group -the better the value. I read that you're interested in booking a sit-down meal. While that is a nice idea, perhaps it would increase the value of your tour time to maybe have that sit down meal before/after your tour? We did a Boma breakfast and had our pick up point be at Jambo House. The buffet breakfast kept us full almost the entirety of our tour time (we only stopped twice, once for churros and drinks, and the other for ice cream and drinks). Being picked up at the same resort as breakfast made things easier and we were ready to go. After the tour, we were dropped off at our resort and had a QSR dinner, a little later than the typical time you would expect (around 10pm). Eating while on your tour can take up a substantial amount of time that could be used riding attractions. You'd basically be spending about $500 for a meal you're already spending out of pocket for. Light snacks and waters were offered to us twice during the tour, so that may also hold you over even more between food purchases. This paragraph is a suggestion, and do with it what you will.
Having your cast member drive you between attractions saves you a ton of time, and it's surprising how being able to cut through backstage areas suddenly makes certain attractions that much closer. Not having to worry about going through security multiple times and waiting in bus/boat/monorail lines felt like a luxury.
While your cast member is willing to work with you on what you want to do, (sometimes at a moment's notice) it's great to allow flexibility as well. Weather, and an attraction going down happened during our time with our guide, she was able to move things originally planned, and seamlessly work in spontaneous attraction decisions. We almost had a stagnant amount of free time towards the end of our planned tour time, and before going to our reserved Happily Ever After viewing area that was arranged by our guide... we had accomplished everything we wanted and then some during our time. Your mileage and needs may vary, bvut it is very possible to get quite a few headliners done in 7 hours.
If you want more specific insight, and know who our cast member guide was; feel free to message me. You can put in a preference to see if a specific cast member is available when making/updating your reservation, and well our cast member was amazing and perfect for our group in our 20s. She was high energy, yet easy going. I would have no problem recommending her. Having her with us for the day made her feel like the 10th family member of our group, and a great bond was made.
In any case, I hope you have the best time during your tour. Also, be persistent with the Fastpasses for your large group... we were a group of 9, and between FP+ and our guided tour; we were able to do Flight of Passage 3 times during our week-long stay without having to wait in standby once.