Strange question- can you play a movie if you have it on a USB dongle, provided there's an adapter to USB-C to play in the media input? It seems as if the media side of the USB-C would do that, but before I go buy an adapter, I want to know if anyone has tried doing that?
Yes/no. The car can't play a video in its stock configuration(US market). However there are ways to get around that if you use an android phone. Maybe for iphone as well, though I don't have any info on that. What you'll need is an app on your phone that is Android Auto(or CarPlay) compatible that can also play videos. Since Google, Apple, and Toyota don't want the liability of a person getting into a crash while watching a movie, you're not going to be able to get an app like that through the official stores. To make it work, you're going to have to take the chance of installing an alternate installer. I've done it to install a YouTube player(CarPlay), but there have been others that haven't been willing to take the risk. It's understandable. The choice will be up to you. You're going to want to do some googling of your phone and the video type you want to play.
Hopefully not while driving. Getting caught in Oregon (not involved in a crash) would get you a fine as high as $1000.00.
Haven't tried it yet, but the Europe manual certainly suggests it can play videos from USB drives. Even discusses the video option screens and my favourite bit was noting that stretching or cropping videos might infringe copyright rules. As an aspect ratio purist, I approve of this warning.