I only care if the insurance premiums will impact cash flow too much and, to a lesser extent, appreciation, which would also be hurt if the flood insurance rates keep skyrocketing.  

I have dreamed of developing the lot, but have no professional know-how in evaluating the financials/costs of new construction, permiting, environmental reports, etc. to come to a conclusion if it would be a profitable/worth my time.

Because he has many other sources of revenue besides our partnership he just wants to be rid of the properties not caring about the financial impact on me.

I know I'm probably 6 months out of cycle on asking this and at the same time showing my ignorance of the income tax code relative to real estate, but I thought I'd ask as I'm trying to make decisions that may be impacted by the answer.   

You would need to see what impact if any a cell tower would have on your existing building and tenants and how close it would be.  

Also look at how resources or boundaries e.g. major streets, highways, parks, schools, commercial districts, etc impact these metrics.Finally, I'd advise to try to go neighborhood by neighborhood.  

The fact of the matter is that as long you can justify that your time, effort and savings realized by this project, as well as its impact on your bottom line then you are made whole.

(that'll obviously impact what strategies are available to you)There really is no one size fits all.

That detail would have an impact on the viability of your investment.  

In my area , storm water management , school impact fees , reforestation , nitrogen reducing septic systems ( $ 20K ) .