There are lot of steps which are totally unnecessary. After taking off the Keboard (Top case). You just need to remove the hinges on both sides and remove the screen bezel. thats all

You went through everything but FAILED to show how to take out the Inverter cable from the mother board. Do we pull up or down or just out.

I am not sure if there is need for removing the right side cables when all you want is to remove the left hinge

Not necessary to remove optical drive and all the cables to replace the inverter