Looking forward to any updates you may have.
I call BS on the removing the front fascia requiring a recalibrate, did my own baseplate (Roadmaster Overland model) and removed/reinstalled my fascia twice, no problems, no recalibration needed. Just don't turn on the ignition or start the vehicle with the fascia removed or that will generate some errors (but even those will eventually clear and not need a recalibration).
I have experienced the same problem getting the transfer case (TC) out of Neutral, however I have now towed about 4000 miles and have found a simple workaround - time. Starting the vehicle and simply waiting 90 to 120 seconds and so far 100% success rate getting the TC out of neutral on the first try. While waiting the two minutes I unhook the towbar and put all the gear away. Perhaps still a "problem" Jeep needs to fix, but for me it is an acceptable workaround for now. Be interested to hear if this works for you and others.
Of more concern is the Electric Park Brake (EPB) activating while towing, I know of two people this has happened to and tires were destroyed. Strongly suggest any flat towers disable the Auto Park Brake (APB) in Uconnect. However, even with that disabled there is a "feature" called Safe Hold that can still activate the EPB under certain conditions, like having the door open or shutting off the engine if the transmission is not fully in Park. You must be very careful when preparing to tow.
I have been posting my experience and details on IRV2.com
https://www.irv2.com/forums/f85/new-grand-cherokee-l-flat-tow-547326-9.html
In particular see posts #100 and #123.