Tool 0 Failure, and replacement parts

I changed the hot end on my creator pro....and must have shorted out wires while doing so...thermocouple wires and heater element wires.

I was getting a 'Tool 0 temp exceeded' error, so i swapped thermocouple ends on the motherboard and it then showed 'Tool 1 temp exceeded'....i think that eliminates the mainboard as the problem moves with the thermocouple.

So I am looking for spare parts, and flashforge charges ridiculous shipping costs. They list their heater elements as 6.3mm and there are lots of 6mm elements on amazon....just not sure of compatibility.

I also was just going to use 1 print head anyway....since I am sick of the other nozzle dragging from time to time.

So a couple of questions....

1. How could I disable 1 printhead.....tool error will not allow me to even access FF menu. Could I for instance, just wire the thermocouple inputs in the mainboard to themselves and complete the circuit, and perhaps disconnect all heating and fan lines for the tool.....would that do it?
I can see having a working second extruder on standby....even if I don't use it, but I don't want to spend $50 on shipping just to have a standby

2. Where do we get cheap parts with reasonable shipping.

3. Is the flashforge heater actually a 6.3mm OD...or is it compatible with the generic 6mm.