Credit score shouldn't be the primary driver of tenant approval, because if they could qualify for a mortgage they probably wouldn't be renters.

I’d love to take advantage of a “traditional” mortgage (or even FHA?)

Private mortgage insurance i believe is not charged on va loans.  

When you go to sell, Montvale requires a certificate of occupancy so this issue has to be resolved in advance of a sale.Although I am not a lender, I assume you will not be approved for an owner-occupied mortgage on 5-units if it is a legal 4-unit without some type of mortgage fraud whether in reported rents, units, or another legal document or representation (very very large issue from a legal perspective with multiple arrests in the last year for anyone playing fast and loose).As far as the DCA, I would recommend coordinating your work with the city with the DCA.

If you’re making a return higher than a bank CD you can support a mortgage.

The quick short answer in my opinion is this: If you want growth stick to the small multis that you know and once the mortgages are paid off retire fully.

You may be able to deduct mortgage interest and property taxes before the property is in service. 

Before you close, can the rent from your buddy and the midterm tenant cover your mortgage, taxes, insurance, plus a bit extra?

Thanks for the heads up, I’ll call the mortgage companies.  

Someone taking out a mortgage for the first time has NO history of paying a mortgage on their credit score, BUT lenders still believe the score is useful!