I was accepted ED, and while most of my midyear report grades are still As, I could potentially get Cs in AP Chemistry and AP Calculus BC because of midterms (this is a worst case scenario and probably not likely––I don’t know my grades yet, but both tests will be curved to an extent and I don’t think I did badly enough to fail them AFTER the curve). Are two Cs on the MIDYEAR report enough to justify being rescinded? Do they even make decisions based on the midyear report, or do they only make these decisions based off of the final report (in which case I should be okay––I am going to work harder in the second semester to bring my grades up)?
You might get a warning. But I doubt they would rescind.
Even if you get two Cs you will not get rescinded. UChicago doesn’t rescind that easily.
You don’t send mid year - you send final.
And no, you won’t get rescinded for C’s. Probably not even F’s.
Your accepted - relax and enjoy what you have left. Real work starts next year 
You won’t get rescinded on 2 Cs in AP classes, or any classes for that matter. You’re doing totally fine. Definitely relax and enjoy your senior year.