They also paid for their medicine for that month. 

. $300Replace bedroom and hallway carpet upstairs $1750Fix missing doorknob on bedroom $180Patch/Paint ceiling bedroom 1 $350New full bathroom vanity, flooring, shower/tub surround, toilet, medicine cabinet, paint $4000patch/paint ceiling bedroom 3 $750New light fixtures throughout $1900You most likely will also need a new roof.

Just my 2 cents...avoid adding artificial smells. 

Better interest rate, but far more importantly you can transition the debt into 30 year fixed rate and lock in an artificially low rate.  

Refinished the hardwood floors upstairs and downstairs, installed groutable vinyl tile in first floor kitchen and shared hallway, new cabinets, faucet, sink, and stove in first floor kitchen, repainted entire interior, reinforced upstairs porch, replaced some support joists for upstairs porch, painted both porch floors, built new upstairs porch railing, installed new vanity, medicine cabinet, and toilet in first floor bathroom.

The cash flow is pretty atrocious as many investors would like to see at least $4,800 ($100/door) the first year, and in your scenario, you wouldn't see that until almost year 15.Your cap rate and CoC ROI don't look bad, but they are likely artificially inflated by the financing structure you have laid out. 

You never want to create artificial turnover.

Plus, there would be no guarantee when the property would sell, realtors would want to show on 15 minutes notice, and there would be open houses with people going through their drawers and medicine cabinet.

Time is an artificial construct, and if we removed artificial light you'd find most people would go to sleep when it got dark and wake up when it got light.

There's still a radical shortage of properties, sky high rents and that's driving very high demand.Education, medicine, biotech, hi tech, defense, finance - there are so many growing industries here that I don't see demand relenting any time in the foreseeable future.