Hero of Iroas

• WWizards of the Coast2013-09-15
  Official Ruling
  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.
• WWizards of the Coast2013-09-15
  Official Ruling
  Heroic abilities will resolve before the spell that caused them to trigger.
• WWizards of the Coast2013-09-15
  Official Ruling
  Heroic abilities will trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times.
• WWizards of the Coast2014-02-01
  Official Ruling
  Hero of Iroas's first ability will apply if you cast a card for its bestow cost.
• WWizards of the Coast2018-12-07
  Official Ruling
  To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.
• WWizards of the Coast2018-12-07
  Official Ruling
  Hero of Iroas's first ability reduces only generic mana in the spell's total cost.

Rulings via Scryfall