Usually, not always, in a sale transaction a seller proves they have good title to convey, they pay for the search, the owner of the policy pays for the policy, the more customary approach, but local custom prevails, it can always be negotiated. 

When negotiating a contract assignment with your end-buyer, what is the criteria used for determining how much of an earnest deposit to ask for, in order to insure the end-buyer has some skin in the game and is not so prone ti back out of the transaction during escrow?

Most people who have participated in residential real estate transactions as buyers or sellers remember experiencing last-minute changes at the closing table.

Focus energy on networking with their foreclosure or collections departments.

While there about 2 weeks I got a  email from a local developer who had heard about the transaction .

I do a lot personal talking to neighbors and others that may have information relative to the property.I've went as far as calling the sheriff's department/coroner's office to confirm death, visited the funeral home and even went to a grave site to personality verify owners' death. 

When explaining notes to my wife just recently I was able to talk about my grandpas transactions and it seemed to immediately convert her thought from 'this is abstract' to 'ok, I get it, this has been done forever, forget the banks :)'

@Eric SchilkI had never heard of that service - that's an amazingly low transaction cost!

Keep complaining to the appropriate city departments (animal control, code enforcement, DMV for possible unlicensed vehicles, etc) while also asking if the other landlord might be willing to sell. 

Generally will need to give them 2-3 months of bank statements so you don't want that transaction to be on any of them.