First, on your rear hatch door. No, it does not always pull down
every time. I find the first time I use the hatch after a battery disconnect I have to close it fully manually. Every subsequent time afterwards, it will do the soft close. I noticed this after installing my battery disconnect switch and using it frequently while working on my stereo.
I can certainly give it an attempt, coding the GMIII (programming rather) to your VIN. I think you have to use one of the WinKFP or PA Soft. Neither of which do I have experience... but they are in my software suite. Waiting to finish the family's covid quarantine before being able to get over to Austin. I have to see a couple buddies over there too. Can make a long day of it.
Pending kitchen pass from the wife of course.