Like you said in the post, if you can complete the houses, you can rent them out, but that leads to the next question, Do they cash flow? 

The duplex is not profitable currently due to the increased mortgage payment and I’m set to lose about $350 a month.

I asked my mom to see what they want  for the house, I have a hunch that it's payed off and they just want to offload it, they mentioned doing a quick close .. the ARV is about $220k and she's kept up with maintaining the property.I'D buy it with hard money, fix a few things while she pays me rent (the hard money interest rate)  and do a cash out refinance in 6 months.Do you think that's a good strategy?  

Unfortunately we bought it at an auction and cannot rent it out so we fixed it up and are selling it, but with this slow market thought of taking out a refi in order to move onto my next project.

Only have about 6 units in my portfolio. 4 currently rented and 2 almost ready to rent.

This would in-turn increase the building value.I have identified total costs and time for this potential change, and was curious what resources or anecdotes you may have to analyze the cost of the zoning change vs the residual outcome and lift in value driven by an increased buyer pool.

Once you own that for a year you can move out of it and rent all the units and move into another one and repeat the process.  

In 2023, we saw the city of Philadelphia conduct new tax assessments and increase taxes all across the board.

For back rent, an eviction isn't enough for some collection agency to go after the tenant.

I’ve got some tenants that have been in my units 10-15 years (prior to me buying them) and are at market level rents.