I honestly have not had this issue, but...
I really hate to admit this but maybe some of you hear this same thing sometimes and for a while I could not figure out what it was, but when in the car alone if the rear or passenger seat belt buckle is turned a certain way, there is a rattle where it makes a sound like there is something loose and the buckle is simply hitting against the B or C pillar making an annoying knock sound. This use to happen occasionally in my 2011 Suburban and it also happens in my 2017. Drove me nuts at first trying to figure it out, I thought the seat was loose or something, but then one day realized what it was and now I just make sure to turn the buckles so they hang and not hit the side panel.
As far as the outside plastic door trim vibrating or making noise, I have not had any issues, but it is amazing after some mileage on these trucks how when you first get them they feel so solid, but after 6 months you start to feel a vibration or hear a rattle of something, could be the road etc, or just that new car feeling has gone away!