I hired a contractor who left his workers unsupervised, they painted the whole house but did a terrible job because the paint didn’t stick.

Isn't it their job orchestrating materials and workers to get the job done?

Selling it.Shortly after some zoning changes came into affect that would have permitted triplexes to be built on both lots.

The licensed pllumber pulls their own permits, the elctrician pulls their own permits.   

In many/most places you can pull permits and do work on your primary residence yourself, but you need to be a contractor licensed/insured to do that in the rental units.

You need to reach out to the local housing committees they will put you on their database and feed your information to their case workers. 

Markets I'm interested in are the Chicago suburbs, Milwaukee suburbs, Las Vegas, and eventually Los Angeles when money permits.

Were all of the renovations you did in the past permitted correctly or DIY?

In general medical professionals are looking for smaller units (studio/1 bedrooms) not 2+ bedrooms- In order to understand corporate demand you should research the types of corporations in the market and figure out if they bring traveling / temporary workers to the area because not all corporations do- You didn't mention colleges but if there's higher education nearby this can also be a driver of MTR demand.

Check local regulations.First, verify that your local zoning laws, HOA rules, or condo bylaws permit renting your property.2.