Congrats on the wedding.
As for your tree issue, well it can be done. I have had a tree come down on child and dog (and all but the tree survived). Plastic ornaments are a must, and no tinsel at all. I used beads. (We had two cats and two dogs and one non-fur kid.) We would tie one or two ropes high in the tree and anchor those ropes to the walls so that the tree would not fall. There is probably no real way to stop the cat from eating electric lights, so you may even have to forgo those for a couple years to see how he does. He may have no interest at all. My cats did well, they loved the ornaments, but never damaged the lights or tree itself. I'm guessing that you could probably buy a spray to discourage the cat, but not sure what it would be. Good luck with it whatever you decide.