You will match them in many aspects .Negativity and poor life choices rub off .

This would be the obvious & preferred choice, Andrew. 

Either of them would be the least expensive and the most likely to finance this, but if they won't because you have no experience or myriad other reasons, know that MOST DSCR lenders won't touch it because it's mixed use.

North and west tend to be more expensive, with the exception of rougher towns like Lynn and Lawrence.How other investors approach these things is strictly an individual choice. 

He has a solid "Deal Analyzer" that will help you with these smaller units.The underwriting tolerance varies depending on the broker/lender and a myriad of other factors.

It might be how good of a deal you got that influences them the most.The Bank might charge less interest if you qualify but they would look more at you instead of the project and usually take longer to approve the loan and it depends if time is an issue with the owner.A Hard Money Lender would probably be my last choice. 

Good choice.

If covering a couple of holes makes them think that they have made a good choice in a place to live, then cover the holes.

In my city, all of the choices you listed.

For me it was a choice.