Someone should also be auditing the books. 

Might it be worth it to pay a company to do a financial audit?

If you get audited, you have to demonstrate that you did in fact hold the property for rental/investment purposes and not for sale.

Escrow accounts are audited to the nth degree.

The debtor's bankruptcy attorney will counsel them on what they can and cannot enter into, a lease would be something to have approved as it is an ongoing debt obligation and the Trustee will need that to determine what amounts are available for creditors.There is no sneaky way of taking any significant amount of money from a debtor during this period as they are under an audit of their assets and liabilities.

It was then that I decided to do an audit of everything.

LLP does not require an audit if the annual sales turnover is less than 40 lakhs and capital contribution is less than 25 lakhs .Tax Registration-Once business registration has been obtained then you need to get various tax registrations.

If they are not reporting ALL of the income to the IRS, they have little to justify an asking price that isn't based on auditable books.  

My professional background is in information/computing security and for many years I conducted audits of corporate information security practices/postures.  

Some Community banks limit the number of Properties (or $) to each Legal Entity or charge Audit fees to review your LLC structure.