This is merely an opinion and a reflection to past experiences, with similar profile of issue,You can consider just calling a maintenance man, have him come out service and verify everything prior to replacing.

Im currently a sales assistant for new home builders and I love the job.  

Mainly because the comps aren't truly reflecting all the land in addition to the 2600 sq ft house.

Please free to reach out, to me, if you feel I may be of assistance, to your Real Estate Endeavors.

My background in real estate:I licensed myself at 18 and became an agent for the company Douglas Elliman and worked as an assistant to the #1 agent in Long Island NY, Joyce Coletti.

The awesome thing about sales jobs is there is no ceiling on how much money you make, and your income is a direct reflection of how much effort you put into it.  

Duplexes appeal to owner occupied so the prices are more reflective of houses as a whole.  

You could hire a virtual assistant to do that for you.

There are many "first time" (not having owned a home in 3 years) buying programs that offer assistance with downpayments as well.  

There I worked heavily with single family housing development (rental and for sale), down payment assistance program, acquisition/ rehab of abandoned properties, and overall community development.