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

Then continue moving from one unit to the others until you renovate them all.

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.

The goal is to continue growing the management business with our portfolio.

If you do decide to help them out and rent continues to be late simply have a talk wiht them and remind them that rent helps pay your bills and since you did them a solid ask for the same in return.  

I strongly recommend that you set clear financial goals and maintain a continuous learning mindset.

Will you continue to add units2.

I believe they will continue to respond to all notices where they are required to do so.

I will continue to expand, and I will continue this path that so far has been successful.

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.