Aloha J.
Wow, you are brave! I travel yearly FROM Maui to the east cost alone with my 2 small children. If you are traveling on the plane with all of those people, you should be fine. Most people would be thrilled to get away from small children, so ask the gate agents and flight attendants to seat you next to or near your party. They will usually help you out to get seats near each other. That way, the chair that you will be kicking belongs to another toddler!! Check the guidelines to make sure that you pack snacks and drinks that are "legal" from the NTSA standards (fluids must be in small containers no larger than...) The plane ride is one of those things that you dread for weeks, and then it is time to do it and it gets done and you are tired, but still alive. It will not be as bad as your nightmares about it.
Once you are there, I hope you are staying at a resort, because that is the way to go with small children. Anyplace that has a beach and a pool, food, interesting things to see (exotic birds and Koi ponds. etc) that require as little transportation as possible for the children. Then, I say, you adults take turns watching the kids at the hotel while the adults go off and play - go snorkeling, volcano watching, etc. without kids. The cliffs and waterfalls of the islands are beautiful, but they lose their beauty if you have a deathgrip on your toddler's pants while he struggles to look over the edge!! It sounds like you'll have 4 kids and 10 adults, so you can leave 2-3 adults with the kids and the rest can go off.
I live in Maui, and I can tell you about the stuff there is to do here. If you'd like to contact me, feel free... let me know where you are staying and for how long and I'll let you know the fun stuff to do!
Pack sun protection for the kids - I use a "rash guard" which is a swim shirt for my kids, less sun exposure and it still looks beachy and fun. Those beach shoes are great too, beaches are not always sandy, some are rocky and kids can't resist climbing on those rocks!
Enjoy your trip!