Taxi vans are kind of small here so not sure if they will fit all of you in. A stretched limo might be a better idea.

You can avert the airport fee by buying a book of 10 transit passes ("Faresaver") from the 7-11 (and one other outlet - drug store?) in the basement of the domestic terminal. You'll need a two-zoner for midweek afternoon usage so that book will cost over $33. Probably just as well take a taxi for that much since you won't be using the transit tickets again.