Meeting with a real estate attorney is the right move, as they can confirm whether the HOA’s claim holds any water.

Do I need to contact the city of Chicago to have the water shut off or is this something I can do myself? 

From, "someone ate my food" to "someone takes long showers and uses up all the hot water" and even arguements over parking spots.Who wants to handle all that extra nonsense for "free"?

Most of your issues sound water related.

There are some great deals up in Pensacola where you still buy a 2/2 on the water with a boat slip. 

Your new potential guests are insurance companies for homeowner displacement (flood, fire), buyers looking to move to the area but not sure where they want to be, sellers who want to sell but have nowhere to go, contract workers in the area, adjunct professors on a semester job, etc.

What is the cost of an HVAC system vs. a heat pump vs. forced hot water vs. baseboard and what is the cost to the tenant? 

Usually as long as their are no life threatening issues (no HVAC, windows won't open, no hot water), the housing authority will began to pay the rent and give you time to address the required repairs.

This includes incentives for green building practices, renewable energy adoption, and water conservation measures.

Just to add ,  not every inspection covers a visual of the septic tank . if they run the water and all mechanicals, they are working fine . other than a visual there are no signs of it not working .