Hi. 
  
On Alamo.com you can rent different type of vans, upto 15 persons, as from e.g. Orlando airport. 
  
I'm sure others like Hertz will offer the same types. 
  
Regarding the passes, I would opt for a Universal flexticket with access to IoA, USO, Seaworld, W'n'W and BGA. I guess Aquatica access is also included since it opened. 
For Disney you have a lot of different Hopper passes available.