I know that these reward the player with a chest upon reset, but committing to these for chests during events causes an enormous drop in idol gain. Considering that, I think events should unlock bonus idols in their free plays as long as 1) All their T2 objectives have been completed, and 2) Bonus idols have been unlocked on at least "World's Wake" free play.

They adressed this by, you have to sacrifice gain for event gear.