Regarding composting . . .
I spent a summer working with someone who was just finishing her tiny house. She had a book on composting human waste. The author even used his waste-compost in the garden. The girl I worked with was just using composting methods as a way to make due without plumbing. IIRC, she was layering peat moss in the toilet (bucket) to control smell and whatever, and then she could compost it in these big containers. I actually don't know what she ended up using the compost for - just the lawn, maybe?
But if you REALLY want to compost EVERYTHING