An quick way to check if the zoning was modified to be a small multi is to check with BGE or whoever supplies power to the home. 

Supply of inventory for one. 

Atleast here in Chicago 99% of deals don't cashflow but there is so much supply that if you watch the mls for a month you can find 5-10 deals that do cashflow well. 

There is less demand, but there is also almost no supply.

Although you have not supplied all the detail (a type of ownership and such), there is another complicated way to report this as partnership return, and their portion of the expenses as non-deductible expenses on your partner's side.

This person will end up paying a couple hundred above materials for this job to hopefully get done right and probably get sold a new trap or supply line or whatever else they can get her for as well since she isn't there.

Plumbing supply would have to come off the main line here. 

Home was purchased as an estate sale in original 1960s condition, there's ample equity given that I made several updates, some as pure sweat equity. 

So there are ample amount of realtors who can help and are seeing this as a new way to buy a home.

Just remember, things happen and contractors usually underestimate the cost of the renovation, so make sure you have ample funds to cover the short fall.