So the very first 2021 we saw and test drove was a white frost tricoat with the teak/light shale interior. That interior was absolutely gorgeous and looked ultra luxury however the wife felt like a black interior was just 'speaking to her'. So a few days later we found a black on black 2021 that was sold but still at a local dealer available to peak at. We both fell in love with the darker theme. In my opinion it looks more modern, sleek, and tough/trucklike. Plus with an infant and toddler, the darker interior I think will hold up better over the next decade we plan on keeping this thing.
You make a very valid point on the need (or lack of need) for rear entertainment in today's device filled world... I feel like we went with them b/c of the age of our kids of course. I've got a thumbdrive loaded with kid cartoons so as soon as we get in I start an episode on my toddlers screen and she's quiet/happy. She's at the age where she can watch the same episode/movie 100x and still be engaged. One way however I can see it useful for teens is movies on roadtrips where you wont have to kink your neck to look down at an ipad for 10 hours. We also have the wifi subscription so I simply plug in a Firestick into the rear hdmi port and I can get Netflix, Amazon Video, etc on 2 big gorgeous screens. I can see that being useful for teens as well. If your cell phone has the ability to work as hotspot you can accomplish the same thing without vehicle wifi. ALSO... if they have Android phones (not compatible with Apple), the rear screens are compatible with Miracast in which they can cast their entire phone screen to the rear seat screen and completely control their phone via the touch screen on the rear seat. So connect their phone which takes 5 seconds, the rear seat screen basically turns into a 12.6 inch HD version of their smartphone where they can control their youtube, social media, etc all on a bigger screen and keep their phone in their pocket. Then of course there are included IR headsets compatible with each screen that can pick up on separate audio streams coming from each screen if playing different content. And also you can connect up to 10 different bluetooth headphones to each screen which I'm sure your teens have a wide variety of.
As far as wheels go, the Denali's come by default with the smaller less attractive 20' wheels. Once you add the 'Denali Premium Package' it upgrades you to the 22' wheels you see in the pic. So technically the wheels you see aren't standard but I'd say 75%-80% of the Denalis I found listed by dealers had the premium package added so the 22 incher will be a common sight I believe. With the size of this vehicle and massive amount of wheel gap... I feel like the 20's would look too small and the 22's are much more adequate. Hope this helps!