The hotel is about 5 miles or 10-15 minutes from the ceremony site. We recommend uber / lyft or renting a car.
Either O'Hare or Midway is fine. O'hare is about 13 miles miles (20-30 minutes) from Le Meridian. Midway is about 20 miles (30-40 minutes) from Le Meridian.
It depends what you want to do-- most of the wedding festivities are in the suburbs, so if you are going to stick to the suburbs, we recommend renting a car. If you are planning on staying in the city and spending time enjoying Chicago, you may not need a car-- and in fact, might not want one because parking can be frustrating! The wedding ceremony, dinner, and after party areas are all within walking distance of each other, so a car isn't necessary. Let me know if you've got any other car questions!