Freon (realistically in this vehicle the A/C refrigerant is R-1234yf) is not liquid when not under pressure, it is a gas...your A/C system may have some dye in it to detect leaks, this is usually either green or reacts to UV (Black) light.
Coolant in the GM Vehicles is pinkish/red, and tends to a more rust red color as it ages...this looks like what you have taken a picture of.
If the road hazard damaged the A/C line (containing the R-1234yf) under the vehicle that services the rear evaporator, the A/C system will become discharged, and the compressor should quit running to prevent damage to it via the pressure switch. This action would not cause a coolant leak inside the cabin.
Now, if the road hazard damaged the "heater lines" going to the rear A/C unit, I would expect a loss of coolant in the engine cooling system and this would be a critical failure. Depending on how big the leak is, and how much coolant you lost, you could potentially overheat the engine; possibly doing irreparable damage to the engine. Normally you would see this rise in engine temp on the gauge cluster, but you siad that the cluster has been rendered inoperable. I still don't think this, in and of itself would cause a coolant leak inside the cabin, unless the coolant line was pinched, or the pressure in the system became so high (due to the overheat), that it blew a hole in the heater core or one of the lines running to it.
I can't recall whether the BCM controls the gauge cluster or whether that is direct from the ECM. Could be either, so not sure, but if you have coolant leaking onto modules under the console, you definitely have an issue.
Since warranty is over (although the powertrain warranty is 5yrs/60k miles), I would follow the advice above. Quit trying to diagnose yourself, stop tearing apart, take to the dealer, have them assess the damages, and give an estimate, and if caused by road hazard, contact your insurance for a claim. Else, you are going to foot the bill for the whole works.
