I’m surprised the members over on the DSM tuners haven’t been able to help you with the wiring issue either… Looks like you may have found that you have a bad TCU??
If you found a burnt TCU, that seems to be a known problem with your vehicle, then I would slap another one in there to see what happens, you might just be overthinking it… That wiring diag just doesn’t look very well done to me… If your TCU is bad you will need a new one anyway…