With regards to your questions:Quality of the neighborhood: This should impact your desired cap rate. 10% cap is good if it's in a "nice" area.

The city is directly impacting your use and value, even though it had been approved of at one point in time.

The building is located in a historic area, don't know if that will have any impact on the insurance.Thank you again!!

Either the true margin is not even close, or you are way overestimating the true impact of 1%.  

Reducing his interest (and thus ownership) of the company by 30%, which is below controlling interest btw, is extremely detrimental to him.He is extremely likely to refuse. 

We have no washers which will impact your costs.

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.  

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.