swapped coils around, I cleaned the whole driver side bank of plugs - surprisingly serviceable (albeit no body on) - still getting the plug#6 misfire

Lund is suggesting maybe the harness is bad... I'd much rather replace a plug first, but I wouldn't think and engine running less than 15 minutes total would foul a plug - maybe just a bad plug out of the box?
we did replaced the power wire to the driver side to ensure the wire is the correct size, we had ~14ga wire in line and swapped out to 16ga which looks to match the rest in the loom.

does anyone have the pinout/schematic of the UEGO sensor wires? thinking maybe we have a bad solder joint in our extensions but would like to understand what each wire is first to tackle