I also know each block down to almost individual houses so makes deal analysis fast as well.

I'm assuming so.Can't you excavate around the exterior of the basement wall (even by hand, if you want to DYI) and install an impermeable barrier against the block and/or a french drain to divert the water around the of upslope side the basement to the down slope?

This almost never will make sense based on zoning, permit, block makeup, and construction availability.

Even in the most depressed cities, there are areas (neighborhoods, blocks) where people want to live and will pay you well for the privilege. 

On nearly every block in my neighborhood in Morris County New Jersey I am seeing development companies buy, tear down, and build new homes, usually gaudy McMansion looking ones.  

If you can get it under contract and it is a great deal, you can sell the contract to another investor who does have the means to close.Anyways your are still in the starting blocks and you have a race to run to get this deal to the place where you are ready to close.I hope this helps.

We had an adjacent AZ property owner put up a block wall and we didn't want the wall.

thats the name of the game brotha, building blocks that lead you towards financial freedom goals for your future!!

With Kensington, the boundaries are thin here in Philly, as you mentioned one block you are experiencing the 'opioid' epidemic and then a few blocks over you are in Fishtown, where value sky rockets.

My first 2 flat was on the same street as my condo 5 blocks away so I knew exactly what I was getting into.