Hey @Ali Farhat - I think your first step is to see how many units the building is zoned for to see if "BY RIGHT" you can add a unit in the basement without the need to go through the ADU program.You can submit a zoning certificate to the city of Chicago to understand the current situation. 

Power company would not turn on without certification from an electrician... of course it was Friday. 

Maybe it will motivate them to make the repairs and give you a Certificate of Compliance so you can move forward.Even if they comply, I would probably file a complaint against both REALTORS once the transaction is closed.

Certifications take a mere 3 days to earn--converting a high school dropout into a licensed and certified technician by day 4.

Gain approval from the city inspector who issues the annual Certificate of Rental Registration.

Here in the Reno, NV area when I work with clients on multifamily properties we get estoppel certificates to ensure that the tenants are actually paying vs what the owner says they are paying. 

Of State to see if an entity is "in good standing", and getting a state lien certificate. 

I have overturned zoning certificates when the seller's agent/attorney said it couldn't be done. 

At most I would give them a gift certificate to go out to dinner on me..... thats it.

In DE you have to give 48 hour written notice sent by certificate of mailing.