I have read through. I think it's a good idea that the OP consulted the BP crowd. It seems that it would be hard to avoid any and all deals that have a whiff of shady around them- in some places you might not make any deals at all. Still, from what you have written this guy sounds like just too much work. I am happy to do my due diligence on a property, but I would feel like I had to investigate this guy, his daughter, and his realtor on the side. Even if it's irrational, that is how i would feel and so I would probably be out looking for the next place.
BTW, I own several buildings built in the 1920s. It seems like between 1925 and the present people in our area were in the walls doing just crazy stuff with the plumbing, the electric, and even the structure itself. I'm not in your area, but anymore we are looking for houses that are not updated because there are so many obvious mistakes out there. What is underneath the granite and exposed brick. And how is the pointing on that exposed brick? Good luck with whatever you decide.