Cut the plastic wrap around the wire harness back a few inches. The wire that's been protected by the wrapping will have much better color coding than what's been exposed to heat and light. Make your cut far enough away from the dash cluster that you have good color codes to follow wen you reinstall the gauge cluster, even if you choose to add a new quick connector. You can solder one end of the new pigtail wires directly to the conductors on the circuit board for the original plug, once you get it dislodged, and eliminate that one really bad wiring repair that's shown in your first picture series. Good luck!
Jerry