LendingOne charges 1.75 points as doing-business fee, but if I qualify for 4.5 and compare to banks where I'd pay 1 point to get 4.5---  with no hope of fast closing, among other drawbacks---  1.75 would be alright.

That deprives your principal of a possible offer.

If the underlying terms are extremely favorable and the principal large, maybe. 

So, if your payments are $1,000 per month, the IRS views them as $990 principal and $10 interest, even if your note states that the interest is 0%.

Cashflow is what's left over after you factor in repairs, capital expenditures, vacancy, property management, principal, interest, taxes, insurance.So it sounds like your not running numbers correctly - underestimating CAPEX which leads to over estimating cash flow. 

I've included an example below to help illustrate this.So different lenders have different rates (which do vary even for DSCR loans) but these are factors they all consider.See example below:DSCR < 1Principal + Interest = $1,700Taxes = $350, Insurance = $100, Association Dues = $50Total PITIA = $2200Rent = $2000DSCR = Rent/PITIA = 2000/2200 = 0.91Since the DSCR is 0.91, we know the expenses are greater than the income of the property.DSCR >1Principal + Interest = $1,500Taxes = $250, Insurance = $100, Association Dues = $25Total PITIA = $1875 Rent = $2300DSCR = Rent/PITIA = 2300/1875 = 1.23If a purchase, you also generally need reserves / savings to show you have 3-6 month payments of PITIA (principal / interest (mortgage payment), property taxes and insurance and HOA (if applicable).

The biggest drawback I am having is calculating cost for repairs & finding a reputable contractor for a fair price - I know nothing about renovations right now.  

The lender will want to see that the income generated by the property can cover the monthly principal, interest, taxes, insurance and HOA (if applicable).

Can the principal balance be satisfied with income from the property or will a refinance be required?

At this point, monthly interest payments had also ceased while it had been reported to us that construction had been completed.Risk MitigationOur Asset Management Team began to analyze and put into motion a risk mitigation strategy that sought to maximize the preservation of principal.