The next day, a plumber installed and had to access underneath the sink.

Once removed, I found linoleum underneath that looked as old as the house ( No. 3 is the yellow, original flooring.) 

-  Etc...Those aren't things that can be looked up on the Internet, and often require several projects before you truly get a sense of what works and what doesn't work.For example, it took several projects in Milwaukee before I truly understood how buyers viewed foundation issues (much of the city is built on expansive soils), how contractors approached foundation issues, and how much it cost to fix the various different types of foundation issues all my houses there had.In Maryland, it took several projects to before I truly understood lead paint issues (Baltimore has wrestled with lead paint more than most cities), how and when it needed to be remediated, and the most cost-efficient ways to remediate.In Atlanta, it took several projects to learn how to negotiate the various permitting and inspection authorities. 

The fact that he made several serious attempts to purchase this property only to have the rug pulled out from underneath him can in fact be frustrating.

If other businesses have contaminents that have leaked into your soil that could be a huge development problem.You might want a developer consultant who knows that market to discuss further.I know nothing of Washington.

Your current owner may have been flying underneath the radar.

In order to get the new dishwasher in, I had a handyman remove the front wooden lip of a tile counter, and plane the wood underneath the tile in order to make just enough room, and then reinstall the lip.Also pay attention to drawer and cupboard door clearance if the dishwasher is in a corner.

Im confused, so you assigned the House underneath a contract for 5000 and They offered to buy The house for 31 as a final offer that you had accepted.

Here in Kansas City it's actually been really dry (in spite of the winter snows) so a lot of the problems are from the soil drying out and shrinking from the foundation, removing the support from the sides and bottom.

But the sheet floor underneath - that isn't clearly visible, so depending on year built asbestos could be present in both the flooring and the adhesive, as @Julia Blythe pointed out.