A similar example was shared around a house purchase where marketing and other business activities uncover a property. 

If you are considering investing in rental properties, you will want to understand how cash flow is determined, as well as some of the most common expenses to account for.Determining Cash FlowInvestors well-versed in determining cash flow will find it much easier to uncover a rental property’s true potential.

If they uncover any thing that they want fixed, you can counter with you've lived there for 6 years and should have known it was a problem and factored it into your offer. 

@Reed Meyer it depends what i feel like learning and what kind of crap i uncover haha.

What websites/subscriptions do you use for skiptracing, particularly for phone numbers, and for uncovering the actual owners of LLCs?

You should be able to make a wild guess based on the marketing, but there are usually unknown costs that will only be uncovered after a detailed inspection.

However upon approval of the buyer's mortgage, the mortgage company uncovered that the HOA did not have proper insurance to abide by federal requirements.

I would have some further conversations with the note holder to try to best uncover how the tenants are doing during this unprecedented time.  

Take a look at this case and the vast amount of detail the IRS uncovered.

There's a lot to be uncovered, and a lot that can happen.