As a maul cannot occur outside the field of play then we should also consider the pace and control of the advancing team. Half a second between a maul and it just being a cluster of players around the ball, second scenario can be brought down as it ceased to be a maul once it crossed the try line.
Wales advancing at speed, not really in control, many legal defenders around the ball preventing it being played away.
I would suggest low probability of clean (clear and obvious) grounding. Most likely held up.
But if that's where the bar is now set then other instances eg line break snuffed out due to deliberate knock on, 2v1 with more than half the pitch width would also be probable. After all they prosecuted a 2v1 in a much narrower space for Dingwall's try.
ETA - Whichever route they decide and given Barnes comments about making the game more attractive I'm happy that greater jeopardy ensues for penalties in the 22m, especially repetitive offsides and killing the ball inside the 5m, stop the game give the PT and the yellow card and move on. But it needs to be, as always, consistent in its application.