If it's a long-term play, the potential savings on PMI with a conventional loan could be significant.Have you compared rates for both options?

I just hope that there's a way to enforce compliance more strictly.As is, the playing field is uneven.

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.

What percentage is fair to pay sellers agent commission and would I be expected to pay buyer agent commission as well?

Redeveloping into mixed use live/work/play projects has been the most common proposed solution the past few years in my area. 

I own a commercial unit, and I’m trying to determine a fair rental rate for the space.

Once that's covered, you can go all-in on those fabulous renovations.Effective marketing plays a pivotal role in attracting tenants and increasing property appeal.

Be prepared for the learning curve with Detroit—it’s rewarding but comes with its fair share of challenges.If you’d like more specific guidance or have questions, feel free to DM me.

If you understand the math of it all it should come very clear, the game is NOT best played (1) buying in all cash, (2) buying and sitting on a property for decades on end. 

Even if they did, the side with evidence tends to win.Your deductions seem reasonable and you are clearly trying to be fair.