@Marco Lopez investing is all about risk mitigation, so if you already have a known red flag and don't feel comfortable then why not look to buy a different property? 

You have identified the additional risks ofa) triggering the due on sale clause, which will likely be present in any conventional mortgage/deed of trustb) the statutory maintenance costs of your LLC (you list CA as your home, so maybe this is the $800 annual fee the state charges)Both of those risks can be mitigated by doing away with the LLC.

Attorney's are created to mitigate risk and entrepreneurs are created to take on risk.

Have a clear move-out date in the agreement.Remember that allowing the seller to stay after closing carries some risk, but with a well-drafted agreement and proper precautions, you can mitigate potential issues and protect your property and interests.

I also looked up Loss Mitigation Network (the lawyer network they claim to work with).

But how can we understand these risks and mitigate them?

Make it hard for them to get in and find what they want.I would never pay thousands of dollars for a mitigation situation that may or may not resolve the problem.

.), that type of storage has, typically, a larger customer draw radius, and low visibility can (in part) be mitigated via marketing.If nothing else, the due diligence exercise educates me and the information can possibly be useful when evaluating other opportunities. 

Looking forward to learning as much as possible and (hopefully) mitigating any terrible mistakes.

Here in Texas, the landlord is required to mitigate damages by making a good faith effort to find a new tenant.