Avenger is a fairly new product, orange oil (D-Limonene) and vinegar. Check your local feed and seed stores to see if they carry it. There may be other products, or you could mix D-Limonene and 10% vinegar to come up with a similar result.
Did you find the DirtDoctor.org source of
business listings? There are organic listings all over the U.S. See if your area or somewhere nearby is listed.
What kind of grass do you have in the yard, and what variety are you planning to sod with? Is there an irrigation system, and will your tenant follow directions as far as how to set it up (water deeply and less frequently, to establish deep roots)?