In my experience I have witnessed and experienced people hitting home runs in areas I would not dare to work in and I know of failures where failing is almost impossible.

Think about all the things that can go wrong- insurance claims, change or fortune, need to relocate, value goes to toilet... and structure to meet those challenges- this can be hand written, signed and witnessed by two not related persons.Gifting you $500000 is a tax mess, I would not suggest you provide gift letter to lender.

It is likely you can simply post the notice securely on their front door, taking a photo and/or having a witness for evidence of posting.

I believe you can take them to court if you can prove that the seller knew that it was an ongoing issue and did nothing to get it permanently fixed (hence you would have your neighbor as a witness to testify).

I will also do more research on lenders as this one was not ideal and I ended up wit 5% more of a down payment than desired.

I’ve witnessed more landlords “selling the house” and requiring it to be vacant, than ever before.

With what I've witnessed personally.

The woman lied and changed her story to say a bus driver was a witness because she was getting on the bus when my dog scared her, but the bus stop is 700 feet from my 7-foot gate.So, people do get sued, but they don't get millions for a bite (not usually). 

The other partner witnessed this and at some point even came to block her from getting too close, he clearly noticed something isn't right there.

I once had to attend court in high school  for work as a witness.