I would not view Lavos as Ahriman... (I am Persian and know a hell of a lot about my ancestral culture).
Ahriman is a deity of pure evil and dischord. Lavos on the other hand... while he may be the one who destroys humanity, he is not really a devil. His intent is not truly known, and thus cannot be compared to a being whose sole purpose is to corrupt.
The entity is Ahura Mazda. I agree with you there. Ahura Mazda is not only the God of Good, but also God of Wisdom. In the more modern version of Zorastrianism Ahura Mazda is also viewed as the one great and mighty God who rules all with eternal light and wisdom. Ahriman is the spirit of malevolance who tries to spread chaos throughout this world.
Also Zorastrianism would make sense in a game where there is a powerful mage named Magus (the title of a Zorastrian priest) and his opponent is Cyrus. (The king who defeated the Medes and the Magi to create the Persian Empire)