Clives is great - dependable and reasonable - I use them every time for airport transfers to/from Negril.

Bird Sanctuary is in Mobay so you may want to do that on arrival or departure. YS Falls and Mayfield Falls are nice but I would recommend having a guide to take you there and stay with you but that is just my preference.
Have you driven in JA before? Make sure all papers are in order in case you are stopped and roadside checks. But if you are "seasoned" and have that many peoples then it might be the better choice than charters which can get pricey.....
Enjoy your FAMILY vacation!!!!!