I probably profit about $0.50/load based on my cost of water and electricity.

; No water/sewer/storm pond or drain.Segregate the analysis of the house and the storage. 

On the flip side having 2 residences in one building does bring efficiencies from a management/ownership standpoint.Finally, the payment structure you mentioned (30-40% until project completion) is fairly standard for pre-construction properties.

Make sure tenant knows how to flip breakers, turn off the water main, relight water heater pilot, etc.

Typically that is 2 per bedroom standard, at least 1 pullout in the living room, so 8 easy. 

American Standard Cadet III.

Tenants pay for gas and electric, owner pays for water.

Home Warranty: My bathroom sink is clogged and I'm too stupid to know how to pop the water stopper out and clean it. 

It will most likely trigger the due on sale clause in a standard 2nd home mortgage so read the fine print.You can always use a commercial loan instead.

As you get further away from standard real estate practice, the risk is increased by a “legal” risk that your protection may be interpreted quite differently than you expect by a court and that the subtleties of the protection a mortgage or trust deed document provide with established law and court decisions handed down for (in the U.S.) 250+ years is not existent.