You might as take the whole loom out of it
Engine loom comes off in one peice, unplug all the sensors, and un-do the earth points, it comes apart at the plug, put to one side.
Remove all the plugs for lights etc, remove the earths, then move onto inside of the car.
remove the roof lining and all the trim down the sides of the car. even the dash as that would make it easier, cit the cable ties used to hold the loom up on the dash, drop the fuse box down.
The door looms are inside the doors and connect to the rest of the loom via the plug on the inside of the door. So basically strip the doors down and put to one side.
The boot release goes along the roof I think, and will be within the main car loom so you might as well keep it all togther, just work your way down the side of the car for all the other wires which go to the reat lights, speakers and fuel pump.
Will take a while to do, but worth it.. then if you do get another fiesta its easier to change a loom than cut one up to acomodate different things