This occasionally happens in my 2015 too. Usually when I hang up one call and make another call quickly. Doesn't drop the call, just have to use the handset until the reboot finishes. Has probably happened 5 times in the last year.
Mine reboots on a regular basis, usually while I’m on a phone call. Planning to discuss with the dealer next time it’s in, but I’m still under warranty.
On #4, I use this:
iSimple ISHD01 MediaLinx HDMI To Composite Video/Audio Adapter Cable (Black) https://www.amazon.com/dp/B00LUX1F5K?ref=yo_pop_ma_swf
Works pretty well, though I have to use a lightning to HDMI adapter from Apple from an iPhone.
I traded my 15 4R for a 15 200. Needed the extra space but had always wanted a LC and the wife hated the ride of the 4R. It’s a daily driver so haven’t done much to the 200 yet, but will eventually, and have loved the 200 so far.