Any halfway knowledgeable seller will want a reasonable amount of money so there's some consequence if you bail at the last second.    

In addition to the strategy I previously outlined, I would recommend you take a good look at your rental agreement and see how you can tighten up the language to clarify your expectations, as well as the consequences for the tenant if they do not following the rental agreement terms.Evictions are costly.

You have pointed out that there are a lot of different moving parts to owner financing and there could be serious consequences if I am pulled into the wrong type of deal.

So that's the purpose of this long winded post, is to  get some opinions as to whether the lender could/should do this, whether it was legal for them, and what type of consequences are there to having taken this action, if any.  

What this thread's content indicates, is that your lease should have a provision and consequences for situations when agreed performance does not occur. 

the mold remediation specialist is right. concrete does take years to cure, which can result in moisture on the surfaces of concrete. as such, any carpet on the concrete slab would eventually cause mold. however, you stated that the floor is tile, so, that would not be an issue. 65% is kind of high for humidity, and given the fact that they have too much stuff in the place, that gives the mold spores something to feed on. consequently, they are causing their own problem. since no one else had such a problem prior to them moving in, common sense says that they are the problem. i would offer them a buy out on their lease and send them packing

We find many times owners want to leave things behind for the tenants to use without thinking about the possible consequences.

At least in Seattle, they follow-up on those and there are consequences.

But now I'm trying to set a business up in such a way to shield myself from personal and professional liability while minimizing my tax consequences.

You want an accountant that can help you strategize and who is responsive when you want to know the tax consequences of the decisions you are making throughout the year.Good luck and let me know if I can be of assistance.