Disclaimer: (This is not a "who-is-the-antagonist" post. This matter has already long been resolved respectfully with an in-game vote. This example is given to point out potential gray-areas over what defines a 2-card combo with the intent to invite thought and discussion on what the nitty-gritty details and restrictions should entail when deck-building combos under the bracket system.)

The other day my playgroup had a bracket 3 match that caused an argument over what constitutes a 2-card combo over a play one of my opponents made. Bracket 3 officially states that there are:

No 2-card combos (before turn 6)

[Combos are] game-enders, lockouts, or infinites

In the game my opponent played a turn 1 Enlightened TutorGC to fetch a Sol Ring, turn 2 played the Sol Ring, and on turn 3 played a Volcano Hellion having it deal 1 trillion damage to itself, but with its ETB ability on the stack they casted Archon's Glory bargaining the Sol Ring to give the Volcano Hellion lifelink which would result in my opponent gaining 1 trillion life by turn 3.

The playgroup insists the play is a 2-card combo that violates the spirit of bracket 3, because:

• The combo was pulled off by turn 3 and not turn 6 or later.
• The combo is a 2-card combo and not a 3-card combo as any sacrificed permanent required to bargain Archon's Glory shouldn't count in a mana-rock heavy format.
• The infinite life gain counts as a lockout since some decks would be unable to realistically break the lock via commander damage.

My opponent and a bystander watching the game argue the play fits within the confines of bracket 3, but for different reasons from each other:

• Ramp and Sol Ring shouldn't be factored in on how early a 2-card combo can occur when deck-building combos, otherwise ramp should count as an extra card in the combo making it a 3-card combo as the ramp was necessary for pulling off the combo early.
• If there had not been any ramping the combo would have occurred by turn 5 at the earliest with no means to win until turn 6 or after.
• The card bargained with Archon's Glory should count as card 3 as it was necessary to pull off the combo which is why they're running Archon's Glory over a card like Swift Justice.
• It doesn't fit the bracket definition of a combo as it's not a game-ender because it doesn't end the game, it's not an infinite because it's a one-time effect that is not loopable by itself, and it's not a lockout because it doesn't impede the functions of anyone's deck and players can still cast spells and attack no differently than before.

There was also discussion if bargaining a token for Archon's Glory would have still made it a 3-card combo if they had sacrificed a treasure token instead of a mana-rock. This further begged the question if and when any card should be counted as being a part of a combo like in the combo Flameshadow Conjuring + Felidar Guardian + Mountain. (The Felidar Guardian always blinks the Mountain effectively untapping it so you can always pay the Flameshadow Conjuring's triggered ability while the hasty token blinks the original Felidar Guardian to restart the loop.) Since the basic land is necessary for the combo, would a basic Mountain count as card 3 of the combo or does it go against the spirit of the 2-card combo rule? Molten Echoes + Felidar Guardian isn't allowed in comparison as it's a 2-card combo that doesn't require blinking a mana source to generate infinite hasty tokens, yet that combo is no less difficult to pull off than the Flameshadow Conjuring variation.

How would you best define what is or is not a 2-card combo before turn 6?