Okay just a somewhat bump.
Polimer managed to get a plane to dive underwater, which is fantastic. Also whatever he’s using for bin2xml is un-hashing pretty much every value that I still have unknown. After looking through it I might be able to get a boat with controls for diving properly.
EDIT: Actually the new SVN version of gibbeds tools is doing the un-hashing. At least I’ve figure out what determines if a vehicle has a rotor or jet engine.