Wiring diagram needed for the BCM and the doors, including ajar switches and actuators, driver seat heater and motors and the wiring in between it and the BCM as well?

This sounds like the DDM is out, but here is the BCM and door lock wiring diagrams so you can go over the outputs and inputs. Also, did you try a CAN scan which can help give you the codes for a bad DDM? You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

As you can see the BCM does not have much to do with the door locks. Check out the images (below). Please let us know what happens.

Thanks for the reply. I should have clarified, these are 2 separate issues that happened at 2 separate times. I was an ASE Tech certified in Brakes and S&S, electrical diagnosis was not my forte.
Issue "A":
Roughly 5 years ago, the Pass Rear Door Ajar issue started, at first it was VEY random, but eventually it became permanent.
Issue "B":
Then approx 2 years ago the Driver Seat stopped moving or responding to ANY position switch input as well as at that time, the Driver Seat Heaters stopped working.

Issue A- Please tell me if my logic is correct.
Today, I went and checked the voltage readings at the BCM Connector C6 terminals a2 (RR Door Ajar) and a3 (LR Door Ajar). Since the LR Door Ajar switch is known to work properly, I got a baseline from it.
With the LR door closed, the voltage at a3 is 10.7v, opening the door causes this to drop to 0.0v
The voltage at a2 (for the RR door) is 0.5v and drops to 0.0v when opening the door.
To confirm proper operation of the switches, I swapped the terminals a2 and a3. With ck#748 (for RR door) plugged into terminal a3, the vehicle recognized the LR Door being opened when I opened the RR door. In my opinion, this confirmed proper switch function in the rear doors.

Issue B- Thinking of plugging in a new DDM/Switch and see if that solves the seat movement and heater issue. What is bizarre is that the adjustable pedals work fine and that switch plugs into the DDM....

The Pass Rear Door Ajar sounds like the latch is bad and I would try the DDM unplugging and check for corrosion on the connector and if okay I would replace the DDM.

I checked the connections as well as the power/ground/fuses etc, and then replaced the DDM. No change.

Hmm, "My driver seat no longer moves" do you have power to the ORG wire at the seat movement controls?