The pulley system sounds like a good Idea. Always wanted to do something like that for a cargo box, otherwise, you're right, it ends up staying up there all the time. I once thought that the amount of extra gas that I end up spending, far exceeded the cost of the cargo box. My problem is before building a pulley system, I need to build the garage to attach it to.
You could easily rig up some pulleys for the spare tire, but another option would be to look for a bike lift. A lot of them are absurdly expensive, but I've seen good quality cheap options at or on Costco's website, I think for just over $10 (or maybe like $15 for two of them?) including all the attachment hardware, which is possibly less than even a DIY project. I think it was rated at 100 pounds, so it could easily be modified to accept a spare tire.
I believe I have Tone's hitch (installed by the PO) and never put any tongue weight on it, but what's the problem? I know I won't break a hitch by stepping on it , but does it bend or break the cladding or the fiberglass skid plate? I'm glad this came up, because I was ready to order the step hitch from e-trailer.
So Kat, are you planning on rotating in that spare, or is it purely a dedicated spare? I'm thinking it would be better to rotate it in. Not only would it be cost effective, as you should get 25% more miles out of them, but it would be a better spare if it maintains the same circumference as the rest of the set. Once your LTZ's are well worn, a fresh one put in the mix as a spare could mess with the TOD, especially on the rear axle. Do you notice a lot of extra noise on the highway with that up there? It does look great with the spare up there, but it looks great without it too. One last question, do you still keep the stock temp tire in the back?