Neutral Safety Switch

Exactly. The "other side" of the NSS is a connection to ground. You do see that with the "start switch", they jumper one terminal to ground? You don't need such a jumper for the NSS since it is built-in. You move the "start switch" to the "high side" of the coil, and do not connect it to ground.

If still unsure how it relates to a normal Mopar starter circuit, look-up a wiring diagram for a 90's Dodge truck. My 96 Voyager is very similar, as I recall. Indeed, the A-413 "torqueflite" tranny has the same or similar 3-prong NSS as yours, and uses a standard "Bosch" relay for the starter.