Wiring Issues on Squire Jazzmaster

The owner of this guitar changed the scratch plate on this guitar and then started to experience issues. On inspection I noticed there was no earth wire attached to the output, toggle switch among other things. The neck pickup was earthed to the rhythm control pots but those were not grounded to anything else. I can only assume the original scratch plate had conductive “insulting” foil which cover a larger area and joined these parts of the circuit. I prefer to use a wire that’s sobered to something solid instead of relying on the pressure of a nut or screw holding two surfaces together.