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.

Fear comes from the unknown, educate yourself and do not buy real estate if you do not have a concrete plan. 

There will always be unknowns  but it sounds like you have a good sense of what works for you and what doesn't and are the kind of buyers who will make sure they have the reserves needed to handle surprise expenses.

I have the strong impression that what I see doesn't follow market "rules" and if that is the case, I must be missing something, and I am not good at leaving things unknown.