Does Skyfall Areion allow hold effects to activate after conquering Reckoner's Arena?

Yes, Skyfall of Areion allows your unit's "When I hold..." effects to be activated when you conquer Reckoner's Arena.

How it works:

1. Skyfall of Areion's Effect: This card modifies the equipped unit's abilities so that its "When I hold..." effects are also treated as "When I conquer..." effects (and vice versa).
2. Reckoner's Arena's Ability: The battlefield has the ability: "When you hold here, activate the conquer effects of units here."
3. The Interaction: When you conquer Reckoner's Arena, you are performing a "Conquer" action. Because Skyfall of Areion makes your unit's "When I hold..." effects also count as "When I conquer..." effects, those abilities are now eligible to be activated by any effect that triggers off of a "Conquer" action.

Important Clarification:

While Skyfall of Areion makes your unit's "When I hold..." effects function as "When I conquer..." effects, Reckoner's Arena itself only triggers its ability when you "Hold" (as stated on the card: "When you hold here...").

Therefore, if you Conquer Reckoner's Arena, the battlefield's own ability does not trigger. Consequently, it will not automatically activate your unit's conquer effects (including those modified by Skyfall). The battlefield's ability only activates when you perform a Hold action.

This is my interpretation based on the card text and Rule 383.4. No official FAQ exists for this specific interaction of conquering Reckoner's Arena while equipped with Skyfall.