Maybe an agent or working as a building engineer for a large multifamily group. 

Many jurisdictions will let you do it if you live there, but once you start getting into foundation work, many require a 3rd party engineer and contractor get involved. 

The guy was a freelance engineer that did work for a utility company. 

Engineer here for what that's worth. 

The Zip code of 48221 is next of the list, here is the link https://detroitmi.gov/departments/buildings-safety-engineering-and-environmental-department/rental-property-informationI believe renovating and selling for top dollar would be in your best interest. https://www.clickondetroit.com/news/defenders/detroit-landlord-jailed-for-code-violations-including-apparent-black-mold-raw-sewage-at-home

Permitting would require getting engineering drawings, plat/survey maps drawn and completing both City and State sign applications. 

Why don't you reverse-engineer and check under BP/Events or on Meetup site where the events that are local to you are happening.

One is telling me to put in the floating engineered hardwood that will go throughout the first floor before anything else.

Electromechanical engineer, with 15 years of experience. 

Both of these boilers are about 3-4 years old.Being an engineer by trade, I first decided to look at them myself in case it's something trivial.