I'm on unity 2019.4.10f1 and Wwise 2019.2.5.7349.
I get no errors in a completely blank scene, but yes I checked the camera for listener and even added a manuel script with registergameobject on start/awake to no help.
In the end we made a new unity and Wwise project and copied the assets and so on over, and finally it works, but I don't really consider that a fix, but we had to move on.
Again, I appreciate all of your help (and the Wwise 301 videos too. (-8 ), and sorry that I can't provide a definit solution for anyone else who encounters this problem, though I think its related to our sharing of files on GIT, and therefore probably an unique error.
All I can say is that I am almost 100% sure that the problem is somewhere in unity's end and not Wwises.
See you out there!