Not an exhaustive list:- how are you providing water?

How old and in what condition are the big-ticket features (roof, windows, doors, flooring, furnace, water heater, etc.)? 

It needed a TON of work when I bought it and the basement had mold and water in it.

Homeowners generally resist lower prices as much as they can, even if that means waiting for a better market.Because of that home prices are also quite resillient to economic depressions; you you look at the last 6 only 2008 has brought a decrese in home values - and that was a special situation.

These are recession resistant commercial properties.

The house has serous basement level water damage which is the major part of the rehab and the master bedroom was framed but not finished.

The inspection came back with some dry rot issues along with water intrusion effecting the siding and may need a full residing / recladding of the building. 

Ask the neighbors if they take on water.

Here are a few other considerations:- Water/Sewer, Landscaping- Annual rental permit/inspection fees - check with your local government. - Are all utilities split for each apartment?

I also want to separate the water heater for the units to increase cash flow by not paying for utilities.