Transportation options: walking, taxis, public transportation, and renting, borrowing, stealing, or buying vehicles.
We have to keep a low profile with any vehicle, and always spoof its ID on jobs. That'll be the case with any vehicle in the group, moreso if we buy a vehicle because then we risk the SIN, the vehicle, and revealing the group as a whole. I think the most reliable option is buy or steal one or more vehicles for the group. I can try to fake the vehicle registration, or we might obtain it elsewhere.
I'm a skilled driver with one fake license. We could pool money from this job to buy a van. We need a mobile place for the unconcious or wounded. Also, perhaps we could take out the rear seat when needed to accomodate gear or Joker's horseman.