We have the body harness tucked away, the important things wired in and seats again! That feels better.

After experimenting with the TCU disconnected we found that all we have to do to get it to crank is give it a neutral signal (or ground). This is dangerous, because now we have hope that we'll be able to throw the TCU out and have everything work... Add this to the list of things that we'll forget about but will bite us later on (update: just found the CAN communication code that it is throwing without the TCU connected *sadface*).