I would fill in with the solid plastic Restoration or similar, a can of non expand window and door spray foam and whatever it took for good looking trimA perfect DIY project for an hour or three. 

That way you have zero disclaimer issues.Basically, remediation looks like this: Turn the area into a plastic bag, suit up in Tyvek, and carry all debris out in plastic bags.

No offense, but just jumping in, as is often recommended, is as dumb as doing surgery on yourself because you read a medical book.

I think in one of those bathroom pictures you have thing wall plastic going right into the ground.

The pipe that comes in from the basement wall is a blue plastic looking pipe.

Flexible pipes usuall aren't allowed, look out for flexible plastic dryer vents!

This is a question for Steven or someone like him, spend a few dollars, go to someone that is an expert on tax law, this isn't something you want to do yourself.Same on protection, find an attorney that has spent time dealing with these things, nothing against anyone on here, but everyone's situation is different A normal individual reading tax law is about like me reading on the internet how to do surgery on myself,,,,its a good way for bad things to happen. andy

Personally I don't think they found anything, but they say there was a plastic p-trap in a random spot on the floor that was broken.

If I needed open heart surgery I'd hire a a heart surgeon.

Seeing how these porcelain (infused with plastic} planks are installed, I don't see how the floor could be waterproof, as it seems moisture could easily slip through the crack between the tiles.