I come from working with engineers, so I am used to it but I can absolutely see how others are turned off 100%. 

Find someone to draft the build plans (draftsman, structural engineer, or architect). 

She will either take you seriously and move out, or she will show up in court with no defensible position and be forced out.The lease says she is responsible for electricity, but the former owner and property manager sets a precedent by paying it.

He is an alleged engineer.

Electrical, plumbing, the list could go on and on.

Your engineer or surveyor or town planning personnel should be able to give some idea of the timeline to having approval and a building permit.

A licensed general contractor or engineer should be consulted to evaluate the wood flooring structures as well as the crawl space ventilation in regards to the moisture and damage concerns.

Check how many electrical meters there are, and if there is one for the common area. 

The building stock is like all the other Chicago urban core burbs, so expect lots of 1950's and 60's construction with galvanized pipes, flat roofs, boilers and outdated electrical.

For example, would you learn on YouTube how to fix your engine if your car was having engine issues and waste time doing so or just take it to a mechanic?