HVAC is listed as system without codes. Which is weird. I haven't been able to find anyone with a tech2 to get another scan and can't buy one yet.Don't think so, There will be other BCM codes for the HVAC.
As for the lift gate switch, that's a five minute job to swap in a new one. For the lift gate, there is a dimple in the rear trim that marks the center for a hole saw to gain access to the switch so it can be manually opened with a screwdriver. GM sells a cover for this new hole. As for why it is all not working, I would again, test with Tech-2 and inspect the wiring going into the lift gate once you get it opened.
The ABS sensors may not be compatible if you did not use OE or ACDelco parts when replacing the hubs. Timken and Doorman also work.
I will have to look up how to do the hole saw thing do you know how big?
I used MEVOTECH wheeelbearings