There are too many unknowns to your question.

@Shane Boyd fear of the unknown and its alot of physical risky work.

Being an engineer I am painfully aware that I is those unknown unknowns that getcha.

Just file the eviction against the tenant, ex-wife, kids, and unknowns at that address and be done with it. 

In real estate, it's not so simple as to make a loan and agree to additional unknown profits for a lender,  everything a lender makes from a loan can be considered interest, regardless of when it is paid, future unknown amounts effect usury laws, points, the status of the lender and their relationship in a project or enterprise.

Most recently, I remember it drew attention when a previously unknown (i.e. forgotten) stream was uncovered in the NE.

After reading the replies I am very curious and amazed that people are willing to give out sensitive personal information to an unknown entity for the privilege of  touring a rental.  

I've got some cash to get started but I overthink and have some fear of the unknown.

In reality this guy is unknown, and seems to have a sketchy reputation.

Sounds like it was a good standing prior; however, she may have some allergies unknown to her and very well can be mold in areas not visible to the eye.