Having bought and sold over 1,000 properties for my own inventory, I had never encountered this situation before. 

I've never encountered an insurance company here raising rates due to the lot.

Have 4 tenants living side-to-side, do you encounter more tenant-tenant issues to handle?

They have no idea what the process is or how many pitfalls they may encounter, which is why a professional Realtor will always have business.

I also had my own Internet business, which brought in consistent income, so it did not take long for me to save for the down-payment on the next property.However, the problem I encountered was that lenders would not allow me to use business funds (non-W2 income) as down-payment.

One situation we haven't encountered is where the PM doesn't want to take on the property due to the area, but I can understand it.

I know how neighborhoods are assessed is relative but in general, if that is your strategy you are targeting the lowest yields in every deal you encounter.  

I've never encountered a problem getting conventional financing sub 50. 

Has anyone encountered this and can help me with some remedies.

Rarely do I encounter hidden items of a large magnitude to justify going back to re-negotiate.If you are playing the numbers game on the MLS, then you are forced to make lots of offers and leave yourself some room for negotiating on counter offers.