Two hands, I am a fan of stats in their place, but if you think the difference in this game has anything to do with frees conceded or that it's even relevant as a key stat I'm afraid you have the wrong end of the stick completely.
A key fact of the game is how good the Donegal defence has been in the tackle, especially when you consider how much Armagh have run at their defence.
Again I'm going to have to disagree with you. The tackles (both legal and illegal) were symptom rather than cause.
The channels through which Armagh tried to attack and the lack of support to the man leading the channel resulted in Armagh running into tackles with no release path. That left them hanging on to the ball and passing, very often aimlessly, to Donegal directly or into no man's land where Donegal were more often not first to the ball.
The reverse was also true, Donegal had a very patient build up and you could often see 7 men lined across the 65, the forwards runs ahead were made to count (both to create space for the attack from the massed ranks or often directly to create the score) and the channels were co-ordinated, that left the Armagh defenders in a position where they had to foul to prevent the ball release to a 3 on 1, or the momentum of the attacker would have carried the attacker past the static defender and again the foul was often conceded.