Maybe a couple of coats of slightly thinned clear nail polish?

That’s the hay loft. Probably more so on older barns, but that’s where the term is from.

If you are gonna let your cat mess with it, I would go with a food safe style finish you would use on cutting boards or the like. Might have to reapply occasionally, but better than running the risk of the cat chipping off and ingesting a more permanent type of finish.

You probably don’t need to add holes to the shelves. There are pegs that go into the adjustable holes that are flattened on one side, and the shelf just rests on them. Should be able to get a set of universal ones from the hardware store for pretty cheap if the originals are missing.

You could always write yourself a simple bash clean-up script that kicks off the uninstall and also deleted the profile and anything else you want gone. Not a universal solution, but if you need to do that one thing often enough it would do the trick.

You’re probably gonna have to experiment a bit. For baking and more delicate things probably the listed fan temp, but for things like roasted potatoes it doesn’t matter as much.

Nitrile gloves have been shown to offer a bit more protection against isocyanates than latex. If you’re just worried about mess and aren’t allergic, then probably doesn’t matter.