These are professionals with additional training and a stricter code of ethics.

My only addition would be to search and analyze deals as often as possible to help you learn what a good deal looks like.

Just cash your checks.As for an up charge due to the additional occupants; charging additional rent for his girlfriend & child would fall under familial discrimination.

We were actually wanting to buy a duplex with it this second time around but the bank was telling us that we’d need 20% down on each additional unit being we wouldn’t be living in it.

We would likely have to add additional egress point for the upper unit via a deck and some stairs. 

These are just some practical questions in addition to the wise "temperament and personality" issues mentioned above.  

(Did you have a contractor look at the building[s]) Are you taking out an additional loan for that? 

Now the house is paid off we are finally seeing good cash flow, but we also are realizing now, that instead of having had our tenants pay the additional interest on a longer loan period, we used OUR money and savings to pay down the interest. 

In addition partner with a Realtor for sales and rental comps and become familiar with the U.S.

You could enter additional Holding costs in the Misc block.