Perhaps the rocket scientists among us who know UAE aviation law can answer this. Is it actually against the UAE law to threaten the safety of an aircraft? Sounds obvious but I know the law against smoking on an a/c has been sitting in some in-tray for years now. This might explain the charges that were made against the trio.
Smooze sailor, the legal action against EY would have more to do with damage control by the three than getting "justice". If they went back to Oz and did nothing they would look very guilty. I would think there will be a lot of noise but in the end nothing will come of it...except unwanted
PR.