I am so impressed by how experienced and knowledgable all of you are.

You can also turn them over to a collection agency. 

Do you have a spare car your not using, a collection that your not interested in or equity in your car or house?

This should help you determine whether you are satisfied with the resulting cash flow after you subtract mortgage, maintenance, etc..As for finding tenants, you can put up posts on Craigslist before you even purchase the multi unit properties and collect as many possible tenants.

If you are rather new, it may influence others to some degree that you are successful enough to swing a new car, you're not a total dead beat (LOL), I see through such things, but others may look to your stature and it may help in obtaining business, a more favorable impression. 

Very impressed with what you found, and your having the crew assembled to do this job so quickly and so well.  

However, if I had  done a thorough background check (housing, income, credit, legal) and it were only one item in question and it did not match up with the other background information I had collected, then I would question the validity of the outlier report. 

Should I collect a security deposit, and upfront payment even though I'm sure he did that with the previous landlord? 

You need to know the following: *Location, Location, Location, How much rent can you collect in this location?

Multi-family units may very well end up comprising either the bulk or the entirety of my rental portfolio once I start collecting rentals.