Okay, I found some video and watched it multiple times pausing frequently to see the actual positions of the ball, players, etc.
I have revised my opinion on the fumble. It is a fumble. Yes, the runner's head hits the ground but the still picture does not show that the ball was already moving before his head hit the ground. From the side angle you can see the ball is coming loose with the runners head off the ground. Look at the second video clip at the :03 mark. Did Dallas recover? From the video I have seen it is difficult to tell if Odighizuwa touched the out of bounds line during the recovery but it looks to me like he did not. His back leg may be over the out of bounds line, but it is not touching the ground so he is in bounds.
The one thing I cannot determine from the video is whether Edmonds touched the ball while he was out of bounds. We need a different camera angle for that. If he did then it is a dead ball at that spot. But the clock should have stopped. The rule is Edmonds has to be out of bounds. The fact he is in contact with Demarcus Lawrence does not make him out of bounds.
Based on all this, the play definitely should have been reviewed and there were only 2 options. 1. It is a fumble and Dallas has the ball. or 2. It was a fumble and Edmonds was out of bounds while in contact with the ball - AND the clock stops.
Would it have made a different? No. Because on the next play Murray ran around Gregory, who was too busy complaining to the refs to pay attention to Murray, for a 1st down just as the 2 minute warning was called.
Video Link:
https://www.msn.com/en-us/sports/nfl/watch-cowboys-robbed-of-fumble-against-cardinals/ar-AASmL9B