Cables are easy, as long as you have decent access if not wire them together and pull back thru.
I'm wondering about the electrical stuff which is way not in my wheelhouse just about to post a thread on that instead I'll tag along here.. The other question to add (maybe you know) is the TnT wire comes out of the handle, not with the other main group of wires. Does it connect to the harness or is it a separate wire? It looks like it is permanently connected at the pump so does that wire go to the battery then another come back thru the harness to the throttle control?