We are doing the same in october, 4 adults and 2 kids, a wheelchair and 5 cases and handluggage! We plan to get the 7 seater dodge and just squeeze in like sardines! After all its only to and from the airport
The Dodge has split rear seats so you can put just half down. I think that unless you go to something like a 12 seater you won't get anymore luggage space.
It's actually going to be 4 adults, wheelchair & luggage now-so not so bad.
Dmil travels light-shall simply reduce the boys luggage as I'm in charge of our