Still trying to dig into much of the setup of the head unit/rear entertainment/etc of the 2011 GL450 (X164) we bought last year.

I'm looking at aftermarket head units, likely something with Apple CarPlay/Android Audio, and have found some info... But there are 2 things I can't figure out...

1) Can an aftermarket head unit with video out be used to play video on the Rear Entertainment screens,

and

2) How do I find out if I've got the Harmon Kardon setup or not (different integration requirements w/steering wheel/etc).

And help would be appreciated.