Removable rear seat DVD+ players/screens

I just bought a new car and it doesn't have any rear seat entertainment. I'm trying to figure out the best solution for my situation. I have two kids.

Hard requirements:
- plays DVD's
- mounts to back of seats (or headrest or ?)
- two screens, one for each kid

Highly desired:
- synchronization between screens so they can watch the same thing
- USB/SD card video playback (MP4, MKV, etc)
- independent sources on each screen (kid 1 can watch either a DVD or USB-based movie on his screen, kid 2 can watch a different DVD or USB-based movie on his screen)
- removable

I have two Android tablets that I could probably find some good mounts for, but they don't have a provision to play a DVD. Is there a standalone DVD player that an Android tablet could use? How practical would this be?

I found a set that seems to fit my requirements, but I can't find many credible reports of quality, etc. Xtrons hd101: https://www.amazon.com/Headrest-Ultra-thin-Detachable-Headphones-Included/dp/B010US5YR0
What is your opinion on this device and this company? What video codecs are supported for USB-based movies with this device?

What other options should I consider?

I would recommend an Advent headrest DVD system if one exists for your vehicle. They are specific for certain vehicles and match the seat material. They replace the existing headrests, so you can always remove them and return it back to factory. They aren't cheap but give you everything you want and are very good equipment.

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sparky