Banks won't even approve these loans because the DSCR is horrible, usually under 1 substantially, not sure how anyone gets a bank to support these deals currently, which is why a lot of them probably do sit on the market for a long time.I think the commercial bubble is very real as cap rates being lower than interest rates normally can't work well unless I am coming in with all cash. 

Your story is just 1 clear example of 1 detail that would take 15 seconds to complete, and how missing it is going to cost you substantial sums of money. 

I'm not saying you won't get some responses to mailing out for owner's of owner financed notes, but most don't want to sell at a substantial discount.  

Investing in properties in SC can work and there will definitely be substantial appreciation in surrounding SC cities (Fort Mill, Lake Wylie, Rock Hill) as a result of continuous Charlotte growth, however, you really need to make sure your numbers if you are investing primarily for cash flow standpoint because of the very HIGH non-owner occupant taxes and school millage rates.

One slip and your net borrowing cost could be substantially higher.

You may want to analyze the property with rental income included but be careful to include substantial improvements in your cash flow or loan.  

My investment amount in this area would be substantially smaller than rentals. 

And usually, the sellers will want a substantial (> 20%) down payment with terms that are usually aggressive (higher rates for shorter terms).

On the final item you list yes this is doable the difficult part is proving it here in OKC and many judges will want some substantial proof.

I'd argue that two duplex properties side by side - one with 2 DUs and 1 with a DU + 1 ADU - would sell for substantially the same so long as each could be rebuilt as is if necessary.