there's a "zero waste cats" thread under Housekeeping. Also a bit of a discussion of "Socks and Shoes" under the Bedrooms topic.
Regarding washing a car, may not be best, but we just use liquid dish soap.
My daughter's elementary school had a Nike reusable program last year. Everyone brought in all the old athletic shoes from their homes and Nike turns them into the playground squishy stuff. I don't know all the details, but a google search might turn up some options.
We flush our cat's feces. Swheat Scoop is the litter we use.
We are not allowed to wash our cars at home. We use a Costco car wash once in awhile (only when we are in that area for other reasons) and a nearby local car wash once in awhile. Both places tout water-conservation methods, but I have no idea how accurate they are...