NOI is NOI . . . the only difference is your cap rate at refinancing might be higher since apartment caps are generally stronger.

According to the Austin Board of Realtors (ABOR), last month was the best March on record for Austin with 2,714 single-family homes sold in the area.  Local home sales grew 10.5 percent year over year in March 2018, a...

They tend to be the only game in town.Conversely properties 3,4,5 million and up are in stronger suburban to to urban core markets where many different types of lenders compete against each other to loan on higher quality assets and better located properties. 

If you are looking to build value and a portfolio, I would buy stronger assets that may not cash flow as much.

If you are holding long term for retirement then rent growth and appreciation in stronger markets over time could outpace cash flow.As net worth grows more investors tend to focus on appreciation and equity growth with tax benefits/  

The buyer could also accept an offer at 170K if they felt it was a stronger buyer or the house would not appraise etc.

“And because of Texas’ diverse economy, we are much more insulated against unforeseen macroeconomic events which might cause stronger economic headwinds in other areas of the country.”https://www.bizjournals.com/dallas/news/2018/05/07...

I would wait to find a tenant before deny anyone.Some jurisdictions require you to process applications in order received, otherwise you can concentrate on the stronger candidate.Sounds like you could benefit from a systematized way to rate applications. 

Your mental state is stronger than you think. 

Bankers can give a stronger pre approval.