Option A would allow me to keep it as a long term rental .

Hi,I am thinking to hire one duplex with two property managers for each unit (as existing property manager taking too long to find good tenant).

The Norris Group has a hard money ADU loan, but it's short term (3 years). 

(long list of things to be concerned with here)What kind of tenants want to rent  where the property is, and how challenging are they to rent to?

Just trying to get favorable terms as compared to conventional loans.

The longer term loans would have lowered your monthly payments and decreased the costs.As for rent, each year you need to look at rents in the area to decide how much you will be increasing the rent by. 

Real estate has long been praised for its dual ability to generate cash flow and appreciate in value.

And even then, the life cycle is generally pretty long from first contact to closing.  

I would find a loan officer that does both conventional and FHA renovation loans to compare which has better rates and terms for your situation.

But if you buy the property well, your downside risk is that it is short term rentals don't work, and you can simply sell it for hopefully no less than what you paid.That would be my mindset.