I would buy one of the water fountains that cycles the water through. Then I would cover electrical cords with the plastic covers. You can buy those at Home Depot or Menards.

As far as buying a second cat, always get a male. Female cats tend to be less friendly and standoffish. I would also buy one that is younger than your current cat because he is used to it being his territory so a smaller, younger cat will feel like less of a threat to him and his space.

Beat the sh*t out of it

There are things you can buy for that, which you spray onto things it commonly chews on and it leaves a bitter unpleasant taste in the cats mouth teaching it not to do it!

cage it