Hi Juniper - bedding definitely, if only because they love to dig

could be straw, sawdust, leaves.... and yes, there will be some random poops everywhere - that is how they mark their territory, but on the whole, most poo and all wee will be in one (or two) corners. You can even put pans there and they will then go in the pans. once you know where they want to be, hang their hay racks just above the pan - they love to eat and poop at the same time.
I also thought maybe - could you plant climbers (grapes eg) so that they can grow above the structure for shade? Any kind of green, growing shade will be better than tarps and shade cloth, and do try for air movement underneath.
Rabbits need to eat about their own body volume in hay every day, plus only a small amount 10% each of greens and rabbit food pellets. This might be a bit different if you are raising them for meat, but happy, healthy rabbits might taste better anyway
