No dings on the background check, respectable jobs in the community, and no red flags during the apartment showing.

I'm pretty certain that it's the same for Americans. 

Most Americans who earn $90,000 a year say they don’t consider themselves rich.

What are some red flags or good questions to ask to find the right fit?  

the majority of Americans live paycheck to paycheck. 

Surprisingly, most that know they won't pass either object (red flag) or don't even apply, saving me time. 

The credit cards are a big red flag.

I would say maybe 1 in 30 files get flagged for this, so IMO, you still will be able to assign the unicorn if it comes your way, which will be rare, but as I said most short sale approvals have the buyer listed right in the approval which would prohibit an assignment. 

Missing rent 15 times plus an eviction is a red flag.

The first "red flag" that i noticed is that i's close to a water treatment plant.