The toughest part of this wasn't setting up different videos to play on each screen but rather the "run videos simultaneously through a web browser" part. So even if you could decode and process such a large video on those Chromebooks, it wouldn't help with video sync. That's not to mention the other challenges with installing the software and getting it to autoload on startup.

You very very likely won't be able to decode a 13660×768 video fast enough.

At least computationally that would be much more expensive and might not work well with weak devices or power saving goals.