Also, regarding your close-up shot of Jenner, if you look at his arm angle, it is consistent with holding a phone and if he was actually holding a phone, it makes perfect sense you would then see the top of it protruding about the side rear-view mirror. That protrusion is not part of the mirror. I think this is pretty close to a smoking gun here.
Still, the accident would not have happened had the paparazzi in the lead car not slammed on his brakes for no reason.