For clarification, the dome switch pictured is at the top and bottom of each door.
I don't see any wiring, but perhaps it enters the body under each switch?
Thing is there are also what I would consider the traditional dome plunger style switch at the hinge point on each door. So that would me three dome switches per door.
Dome light switches for side and rear doors are placed in the doors themselves or along the hinge pillars of each set. The parts in question are as mentioned to minimize rattles as the door would move or "flex" when closed and the van traveling.