They determine the mold is due to; (1) tenants causing crazy high humidity basement humidity by running the dryer without ever cleaning out the lint trap and (2) not cleaning the bathroom- All mold is abated with bleach, a second dehumidifier is placed in the basement, carpets are lifted, trim is replaced, and we investigated behind walls.

I wanted to clear a few things in case It happens again.In a deal like this, how do you guys deal with the HOA, meaning, do you investigate about active/potential special assessments?

It is worth investigating. 

Verifying work and references is crucial, and do your investigative work to determine if the person is good or not!   

one month without explanation, I found a random deposit of $125 on the Friday before the end of the month, March 29th, before I could investigate on April 1st $227, Saturday,April 7th $350, Sunday April 8th $53, Friday April 20th $95. 

@Chris Pohlson I have run into the same problem as I investigate lenders as I am approaching my final conventional loan.  

If a home at 40th and Byrum has good numbers, I would investigate further.

I live on the north side of Chicago with my wife and son.I've been diving into strategies around innovative short-term rental investing (airbnb, VRBO) and trying to investigate whether a lease-ro-STR model can work in Chicago. 

The utilities are turned off at the moment, so how does one investigate the state of electrical, plumbing, sewer etc?  

No idea what they will say about your scenario if they decide to investigate.