You need to sit down with a pad and pencil and develop a plan on how to proceed with this.
This is either the first demolish and rebuild or you do it wrong every time. You need to remove all pipes, wires, and fixtures for starters. You don't walk up to a bathroom sink and try to break it off a wall, leaving the remnant hanging with pipes still in the same location. There is little likelihood that wires and switch locations can be maintained throughout the build.
Try to develop more thought into all of the processes. It's not difficult at the demolition stage but will be critical at the installation stages.