Kirol, History Buff // Pack a Punch

If an effect instructs you to choose a card name, you may choose the alternative prepare spell's name. Consider only the alternative characteristics to determine whether that is an appropriate name to choose.

If a prepared creature loses all abilities, it won't stop being prepared, and nothing will happen to its alternative characteristics or to the copy of its prepare spell in exile.

Casting a copy of a prepare spell from exile isn't casting it for an alternative cost. Effects that allow you to cast a spell for an alternative cost or without paying its mana cost may allow you to apply those to a copy of a prepare spell cast from exile.