Here is what I know so far. You can find Chicago Harbor fees for all the marinas a Chicago Harbors - Westrec Marinas
. It lists fees like additional parking cards, later leaver permits, etc. If you are a liveaboard you are not considered a Chicago resident so you pay a non-resident surchare of 25%. The season runs from May 1 to October 31, with late leavers allowed to stay until November 15th at Belmonth, Diversey and Burnham.
Additionally, you cannot have your head connected to a Y-Valve even if you locked in the closed position. I have never heard of anyone being inspected for this, though. There also can be electrical usage charges based on your boat and if you are running AC or a refrigerator, but that seems to be on a case by case basis.
Additional information can be obtained from Westrec Marina Management by calling 312-742-8520.
I don't have the phone number for River City with me today. I am told that the slips are privately owned so you need to contract with a slip owner for the winter. I am not sure what services they provide in the winter. There is usually plenty of parking around. There is also a Bally's health club in the condos there so membership would be great for showering and staying in shape.
Please let me know when the article comes out. I would love to see what you dig up through your investigations.