Sorry you got no responses so far, but week ends are usually pretty slow on the forum.
As for wire bottom cages, you can put any type of rabbit safe litter in the drop pan. Shavings or compressed wood pellets will work well.
I normally don't use any bedding in my cages, just the solid floor and litter in the litter box. Rabbits do enjoy lying down on a solid, cool floor. I will give the bunnies a bed or blanket after they are fully litter trained, because they normally pee on it before then.
For litter training, I find it easiest in a solid bottomed cage (I've never actually done it in a wire bottomed one). No bedding, no blankets, just the solid bottom and litter in the litter box. When the bun pees on the floor, I soak it up with tissue and put it in the litter box, and then clean the spot with 50/50 water/vinegar. I clean the cage bottom multiple times a day, often 5-6 times. Keeping the floor bottom clean and the litter box a bit dirty (put a little bit of dirty litter in each time you clean it). The bun normally catches on with in a couple of weeks.
Of course, spaying and neutering really helps too. Young bunnies are often difficult to litter train until they are spayed or neutered.
As for sore hocks with wire bottomed cages, you can provide a resting board for the bun to sit on. That can help if you are concerned about that.
-Dawn
