Wow.
Only thing in common with all that is that it is electrical. I've heard others in the past with similar problems. The answer (so far) has always been a bad ground or two (or three...).
Would suggest checking your primary grounds (should be one going from battery to engine and another going to the tub on the firewall). Would also check the cable bundle that comes out of the cab into the engine compartment (on the firewall above the clutch pedal). Mebbe some of those have gotten worn down.
Other than that its a lot of trial and error testing of the specific items you listed.
Good luck.