The seller has the two lots legally separated, but due to deed restriction imposed by the subdivision development, found that building a house on the “tennis court” lot was not allowable. 

If you need financial help, ask under the "Finance, Tax, and Legal" forum.

Do not rely on it for legal advice.

- Also, what is their networth, so they are legally collectible for the guarantees?

Much better than a legal filing or media attention. 

Nothing in this post should be construed as, or relied upon, as legal advice or as creating a CPA-client relationship.]

Prospective investors should carefully consider investment objectives, risks, charges and expenses, and should consult with a tax or legal adviser before making any investment decision. 

. - For Both Parties: - Use legal agreements to outline roles, responsibilities, and profit-sharing. - Communicate openly and regularly to build trust.

J Scott, one of the more respected authors/authorities on BP, provides scenarios in which wholesaling can be done legally and ethically.  

It's a place to legally go and sell stock/business without capital gains.