While I don’t specialize in multifamily properties, I have worked with many investors in the single-family sector.

Is $107k your true net, or do you have any other expenses (mortgage, taxes, lodging taxes and fees, insurance, utilities, landscaping, WiFi, etc.)?

I'd recommend looking at costs. your build cost is going to be well over other homes because of the fixed costs like slab, Hvac, roof, etc. check the market drivers and weight the benefits of short term versus long term. long term is no furniture and help pays mortgage but at this size it doesn't really cover everything. we didn't find a lot of economies of scale in single family detached. can you build more than one unit?

You want to look for like/kind SOLD properties to compare so, single family to single family and multi to multi (2-4). 

The way I understand it is if you were to say, have a fire (even while vacant), and put a claim in with your insurer and they find out you have been utilizing the property as an STR they will deny the claim. 

The pro development and affordable housing advocates use the term NIMBY, but I suspect it is the rare person that buys in a single family zoned area that would be thrilled to have 17 units (qp16 additional units added) in the lot next to them.My initial protege was the land source on this effort.  

My original plan was to utilize a real estate agent to be my property manager that I met through a Dave Ramsey referral program, but I'm exploring if I should attempt this on my own.  

Single.

There are quite a number of things that can make utilizing an FHA loan more difficult such as more barriers during appraisal, appearance of low qualification/little cash, typically longer closing period, likely higher interest rate, and PMI cannot be dropped without a refinance if 3.5% down.That said, just chain 5% down conventional loans, and make sure your duplexes pay for themselves.  

Great question - 20% down is the typical down payment for investment properties, regardless if it's a single family, duplex, tri or quad.We have a 15% down option for the same type of loan.