FIXED!
Finally. After several months and many hours, everything works. Headlights, parking lights, hazards, brake lights and turn signals.
The last two to be resolved were the brake lights and turn signals. To diagnose, I took the switch completely apart (for about the 10th time), but this time, I plugged the raw switch elements into the harness, like this:
(that poor circuit board)
With the rocker absent, the brake lights came on perfectly.
I played around with the angle of the rocker tabs and moved it back and forth with my thumb until everything worked.
Conclusion: The rocker tabs were FAR too "flat." They need to be bent upward at a fairly decent angle, like so:
Reassembled everything, and it all works. Thanks to all for your help and good advice. Special shout out to Steve for his wiring diagram and input.
* * * * * *
To summarize, here were my issues and here how they were resolved:
Uncertain about steering column wire connections: Referenced pics on the internet and consulted wiring diagrams.
No parking lights, and 20A fuse was popping every time I tried to turn them on: Front left parking light wired backward.
No brake lights or turn signals: A combination of cleaning out the TS and hazard switch contacts, re-soldering loose wires and bending the rocker tabs at the correct angles.
Thanks again. On to the next issue, lol.