I have seen cleaning companies do it as well as other businesses.

The rest is just clean up.

If you have a contact for a good drain cleaning servicer at a good price let me know.

I am replacing a lot of old electric stoves in my apartments to use gas stoves and use the 220 line to make new 110 lines to help the aging electric system.

It would work fine as adu the financing is the biggest thing, I personally have shipping containers as storage and with adding roofs and welding the containers to the foundation and adding perm electrical they still consider personal property.

The sellers claimed it was cleaned up but upon a re-examination we found human waste STILL in the basement, not to mention the guy cleaning it up was just a maintenance man and had not come close to taking  appropriate measures to rectify (a shovel and hose doesn't clean up bio waste).

Just when we were about to close escrow, the house was finally cleaned out & vacated.

Do you have any other contractor contacts you trust for other work (sheet rock, electricity, plumbing).  

High efficency furnaces vent out to the side of the house, water heaters as well, or go electric.

Pretty much any local lawyer should be able to help you but most the people I used to work with would probably be able to write you a clean operating agreement cheaper than reviewing one you wrote.