Yes the Iranian and American Parsis require voluntary admission with knowledge.
I have to say you are doing very well in your studies. You've grasped the one thing that people have a very hard time grasping. That it a very individualized religion. The Navjote begins your relationship with Ahura Mazda. We learn from Him and His creation. Zoroaster is not like Jesus. He's not an intercessor. We deal directly with God. The Zend Avesta isn't really a "Bible" per say. Zend means commentary and Avestan is the language it was it was written in. It's Zoroaster's prayers to Ahura Mazda and tells of his relationship with Ahura Mazda. We use that pattern our own relationship with God after. So when you have many individuals in a a personal relationship with God instead of God having an exclusive relationship with an intercessor. Then yes you get many diverse views.
Zoroastrianism is but one sect of the greater religion of Mazdaism. There is also Manicheism and Zurvanism. The Manichean's were persecuted for their beliefs and Zurvanism is considered to be blasphemy. But in the Navjote one of the prayers says the Ahura Mazda and Ahriman were born of the same womb. The womb they were born of is Zurvan's. The Zurvanites believe Ahura Mazda and Ahriman to be twins. Polar twins but twins none the less. So good and evil are twin forces. But Good is the superior force. The war in Heaven and the battle between good an evil are classic Mazdaism. Zoroaster explained this battle and the workings of the universe to Kaye Vishtasp with a game he called Asha (Righteousness or Wisdom and truth as one.) To day this game is more commonly called chess. So Zoroaster also has the distinction of being the inventor of the game of chess. That's why it has white and black game pieces. The white pieces is Ahura Mazda and the Amesha Spenta (Angles)v. The black pieces Ahriman and the Daeva (Demons.) The game is a dualist battle (Dual forces) between Light and Darkness - Good and Evil. In his day Zoroaster was known as the wisest man in all the world.
One last thing. Lately I've seen shows where they look at religions for the possibility of contact with Space Aliens. Like Chariot of the Gods stuff. Zoroastrianism would blow their minds. The Faravahar is supposed to be Ahura Mazda emerging from Asha (Wisdom and Truth as one.) But it also looks like a man emerging from a space ship. The greeks very bad at translating Avestan and Pahlavi. They gave us Xerxes for Shahanashah (King of Kings.) But they got one right and it was really right. Zarathustra and Zoroaster comes from Zara Ustra. It means Camel Rider. Zoro is the greek equivalent of Zara meaning rider. But instead of the greek word for camel they used Aster meaning Star. So Zoroaster mean
http://www.youtube.com/watch?v=-Sj-sDmvRpk">Starrider.
One of the oral traditions tells of Comet that struck a mountain in Iran. Kaye Vishtasp went to survey the damage to Kingdom. When he arrived at the mountain.
http://www.youtube.com/watch?v=YdO_CmfFKYE">The entire mountain was on fire.Out the flames, dressed in fine linen, came Zoroaster. So in some sects it is believed that Zoroaster came to this world riding upon a comet. Also it is never said that Zoroaster is or was Medean. He is described. It always says he appeared to be Medean. You'll not find this written anywhere. To this very day, 9,000 years later, it still survives strictly as an oral tradition. It's also called the secret origins of Zoroaster. The Magi hold many Secrets. But when asked Questions. We give answers.
Btw, Walt Disney was also fascinated with Zoroaster. Watch Bedknobs and Broomsticks. In the King of the Jungle's (A lion:See Zurvan) book upon the page is "The Charm of Zoroaster." Magic means the Art of the Magi. That encompasses many many sciences. Because we follow a Wise Lord. Look at all the science behind the "Magic" of his Kingdom. ;-)