hahahahahaha! this is very funny. I don't see why not, but i wouldn't. It would probably need to be quite complicated to make sure it was sterile, like treating it and heating it or something. Compost is good.
I don't see why not. I regularly add cowdung to the soil as a fertilizer boost. Just make sure you grab the poops that come from the second digestion (Dark brown not the greenish ones that the rabbit re-ingests