In my opinion, the answer to your question lies in what you project the expenses of the sales side of the business will be. 

A simple project that should have taken 2 months took him 9 months.

Or should I sell in the near future?

As my colleague, @Savannah Yingling,here at District Invest Group just stated, we have some local experts and clients making a living in Baltimore projects and agency as well. 

First time poster here and new investor, appreciating any advice in this new and scary world.My project, a conversion of a single family unit to a multi-family unit, is delayed by about 5 months. 2 months of the delay is due to my mortgage company.My original mortgage company transferred the mortgage to a different mortgage company early on, and did not give me the required 15/30 day notice.

Let others leave their future in someone else's hands, but not you.”

If the lenders are ok with it it could be a great cash flow strategy.One more thing to consider is what a future potential buyer might think of the strategy.

All the rain and the freeze/thaw cycles speed up the degradation of masonry work, wood work, paint, and can cause many other issues that don't occur as often in warm, dry climates.Regarding your appreciation estimates: in a C or D area, you may or may not get 3% property and rent appreciation--lots of C and D areas depreciate (without a LOT of data and research, it's impossible to know what the future holds...and even with a lot of data and research, it's impossible to know what the future holds!). 

This was a seller-financed transaction, the terms allowed us to use the ground as collateral and I brought partners in after I got all of the city approvals, and they took over the future expenses for the seller financing note and the other costs like engineering.

I have some more reading to do but if I understand correctly I will assume title under the Ladybird Deed and can just continuing paying the mortgage from my parents current mortgage yet not actually "assume the mortgage" and not have it impact my eligibility for a future FHA financing.I may have awkwardly described what may be the strategy.