Suddenly lost all function on power locks and windows, alarm system, interior lights

Assuming all these are related which is always hard to assume but in this case, the body controller is responsible for all these items. So let's start with one issue and fix that and if the BCM is causing that one, I bet it will fix all of them.

I attached the wiring diagram and we need to test voltage coming out of the BCM on the green wire (input to the BCM from the switch) and then the tank wire on the BCM. This is the command wire. So I suspect you will have voltage at the BCM on the green wire and then nothing on the tan wire. If that is the case, replace the BCM and hopefully all the issues will be fixed.

Let me know if you have questions and we can go from there. Thanks