Question about my (new to me) Lionel Lion Chief Plus 0-4-0 A5 UP Locomotive

Front Coupler, head light, marker lights, cab lights, if any. Can motor, you mentioned. There would be at least one wire for the TMCC antenna, but probably part of the tender.  Smoke unit power, if TMCC controlled. Sometimes there is a chuff sensor, that syncs the chuffs/puffs, to the drive assembly, requires a couple of wires.   An older Seuthe smoke unit, would take a couple of wires. ???

Answering my own question after opening up the tender:

The 6 wires go to: power + and -, speaker and rear coupler.

The photo in the parts diagram was not clear.

Now I understand!

Lionel hacks up a production engine to show those pictures, so frequently the wiring doesn't reflect reality.  Many times, wiring harnesses aren't even shown in the exploded wiring diagrams.