Take care and investigate issues in your area.

There are basically two ways a lender begins to investigate or start the DOS issue with their borrower, formally and informally, a registered letter or a phone call.

I'm still investigating, but it appears that my evidence is solid and compelling.

Disciplinary action by Commission.the Commission may investigate the actions of any person or entity licensed under this Chapter, or any other person or entity who shall assume to act in such capacity. when the code says "actions of any person or entity licensed under this chapter."

You should check with government agencies to investigate the company.

Regardless of the location, I still think that investigating the due diligence is the same for any location.

Accounting wise, you can dig and work some accounts backwards to obtain great insight to any business, this may require an auditor if you are not an accountant, depending on the operation, it might be a good idea to get professional assessments, prior to closing.I say prior to closing as you can make your contract contingent on verified income, expenses, etc. with such being a final investigation after a price is agreed to.

Even if their DOI asks that question, which I have seen, I would expect an affirmative answer to elicit further investigation into the relationship.  

Understand I do not know much about residential financing, so take this with a grain of salt, but it may be worth investigating more:It's going to cost you money to refinance, and the long term effects of the higher rate are significant. 

Unfortunately for you, your immediate interests will not be paramount.Without getting involved you may want to investigate practical alternatives.