Heroic abilities will trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times.

Heroic abilities won't trigger when a copy of a spell is created on the stack or when a spell's targets are changed to include a creature with a heroic ability.

Heroic abilities will resolve before the spell that caused them to trigger.

If a land that hasn't been under your control continuously since your last turn began becomes a creature, it can't attack and its activated abilities that include can't be activated. Notably, it can't be tapped for mana that turn.