So:
1) In the first stage, if a mirror match occurs, you need to restart, not play a second random game. That is, mirror matches are prohibited in the first stage!
Why not hold the final to five wins? It would be more logical, and then you could combine the 1st stage and the 2nd stage, and the 1-2-...-2-1 scheme?
But there should still be 4 games.
4th place in the second group isn't such a loser
1-5 2-6 3-7 4-8
No brains, you can't reach the top just on luck
Except the ones we've made