Beating a dead horse here.

And it sounds like similar to your town, that building's age is the norm and the young professionals aren't racing to live in the cookie cutter homes 20 minutes of town.  

In the last 2-3 months HUD came up with new guidelines regarding against criminal background as a protected class such as race, gender, etc.  

Here is the Seattle definition: “Discrimination” means any conduct, whether by single act or as part of a practice, the effect of which is to adversely affect or differentiate between or among individuals or groups of individuals, because of race, color, creed, religion, ancestry, national origin, age, sex, marital status, parental status, sexual orientation, gender identity, political ideology, honorably discharged veteran or military status, alternative source of income, participation in a Section 8 or other subsidy program, the presence of any disability, or the use of a service animal by a disabled person.

No exceptions, and keep the kids, age, race, etc. out of the equation entirely.

For example, service horses are federally recognized as a service animal.

Then she said that I just did not want to rent her because of her race, except she put it a lot more blunt.My question is does it pay to try to understand the tenants income while in the vetting process or should I just run the numbers and either qualify or deny based on that and not go the extra to try to understand if there is more income or if a 100 thousand dollar debt is going to be forgiven?

Just in passing...I once owned a Whippet (as well as 3 rescued retired racing greyhounds). 

A service dog can ONLY be a dog (or rarely, a miniature horse).

Looking back, I think a few things I did right (at first by lucky accident, and later by deliberate planning) made this possible:1)I timed my appreciation plays very well ... not that I nailed the absolute bottom of the market upon purchase (though I have), but like horse-shoes, hand grenades, and nuclear warfare, close is sometimes good enough.