Seems like a lot of people are recommended them here. 

First thing I recommend is to figure out your target market.

I would recommend having a conversation with your tenants and letting them know of your interest in selling the property to gauge their interest in terminating their lease early - or if you have a termination clause, invoke it. 

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.

We were using a 4th (not on your list) but I cannot recommend them. 

You'll end up in court with a lease agreement that says rent is $1, and the recommended tip is $1,999.

I recommend you get a pre-analysis on the tax benefits available to you on a particular property either as soon as you identify a property or once you have closed on it.

What is the recommended R-value to use?

They also have calculators to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

None of which I would recommend.