Sorry, but thisisboo, you're incorrect.
Since you control the
Favored Hoplite, you get to choose how the two competing prevention effects happen, see Comprehensive Rules §616. You can decide to have the prevention effect from Acolytes Reward take affect first; the damage is prevented, and you get to deal X damage to target creature or player. Then the prevention from the heroic would happen, preventing any damage that wasn't stopped by Acolytes Reward (eg. you're devotion to white is only 2, but something is trying to deal 3 damage to the hoplite.) If if you have enough devotion for Acolytes Reward to be able to prevent all the damage, the prevention effect from the heroic trigger does nothing.