I am also an investor that does flips, has rentals, lend my own money, has owned STR and have been a member of the local REIA for over 10 years, So hopefully my experience and network of other investors could prove useful in evaluating the potential of the property and possibly attract a partner if you need. 

Which background check sites are used for hiring employees rather than tenants?

In our market, I figure I'd need 65 units to afford to pay a w-2 employee to manage for me-- but I probably won't since I really don't mind managing.

One of my biggest concerns is evaluating properties.

I actually have two clients right now seeking some evaluations due to flooding (we have had CRAZY rain the last month!)

This will help inform what other factors you should be considering when evaluating the investment.   

Zillow, apartments.com, outreach to local companies that common sense suggests would have project based 1-3 month employees.

Seeking guidance on:- Filter Criteria: Key factors for evaluating multifamily properties in Texas?

Multifamily homes often require more maintenance, so factor in potential repair costs when evaluating a property.

As a postal employee, he has a guaranteed pension, but not a lot of savings -- I know, complications, complications).