Sorry if I missed some posts. A few quickies:

The alternator in my 1985 300D is termed "Motorola-style" on a web-site about them. Also used by GM at that time. It has self-generated field power, which has to "boot up". It uses current on the return side of the dash bulbs for that. Originally just the "BATT" bulb, but looks like from 3 dash bulbs by 1985. If your dash bulb(s) doesn't light on key-on, the Owner's Manual states to immediately drive to a dealer for "emergency bulb swap". Today's owners are hopefully less helpless.

If you use LED bulbs in your dash like me, that doesn't provide enough "boot-up" current. However, there is generally enough residual magnetism in the rotor to boot-up if you rev >1000 rpm. The dash bulbs go out once booted-up. The OP sees that, so has no real problem.

If you want an emergency fix, the blue exciter wire has a connector clipped to the aft side of the coolant reservoir (1982-85 300D). You could unplug that and apply current to the alternator side of the connector, with engine idling. I wouldn't apply 12 VDC directly since might smoke something. You could carry a ~100 ohm resistor between BATT+ and that connector to provide a reasonable boot-up current. Of course, just rev'ing the engine is much easier if that works.

Re. BATT- ground, there is a thick ground strap between transmission and frame on the driver's side, off a bell-housing bolt. Corrosion there was a problem for me once, which I noted because I saw smoke from the speedometer cable as I cranked the engine when the dash was pulled out, so it was using that metal as the ground path. Since aluminum oxide is a poor conductor, I removed that connector, sanded all surfaces, coated with silicone grease re-bolted. This was in a CA car, so I imagine much worse in the salty North. Also, clean the BATT- to frame connections right by the battery. Cleaning battery terminals is an annual task in the East, which is why even grocery stores sell a battery brush.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans