Holding onto them will more than likely increase their value over time, along with all the equity you built through the flip.

And depending on how the unit is built, the owner probably pays for water and sewer, maybe even for heat. 

Nobody planned to leave their cash stuck in it, and we had built massive equity. 

I explicitly and specifically built GrumpyHare to fix and overcome ALL the shortcomings of all other templates.

But I would be missing items necessary for taxes, etc.

Unfortunately, @Jonathan Greene, in nearly all municipalities, fire escapes cannot be newly built and added onto a new project.

@Gino Barbaro Built in 1947. 

This is bogus if buyer and seller are independent parties (if the parties are associated then I understand setting true value) as there is usually a reason for the discount purchase (risk items like unpermitted work, crazy low rents in rent controlled area, hoarder, heavy need of rehab, etc).  

Do not count on anyone to get the contract assigned to them until you have had multiple conversations with them and you have built rapport.

We don't like SF houses that have been hacked up into apartments, only buildings built for multi.