Ugh.

Sorry to hear that. I was hoping for you that the easy, simply remedied problem with the ground connection would solve the problem.

At this point I'd double-check or redo the wiring splices you did when you did Option B. After that, I think the next step is to remove the shuttle valve switches and inspect for brake fluid, inspect the wiring for deteriorated insulation, and check the resistance of the switches.

Please let us know what you do next and how it turns out.