Sharif in the article is correct to say that Zoroaster was not a prophet, since there is no evidence of Zoroaster, himself, ever claiming 'prophethood'. Though I appreciate your view.
The other main 'philosophy' or key point, to which Sharif alludes in the article, "For me he is a prophet", is that Zoroastrianism is a *reflective* (not prescriptive) faith; meaning it provides clear guidelines for belief & ethical behaviour, which you must consider carefully. But you're also free to seek truth & choose according to your free will.
Jesus as the Saoshyant is a good way to evangelize to traditional Iranians.
Yes. In fact there are people who have converted to Christianity from Islam, even in Iran. But practice their new faith privately, because the punishment for an apostate in Islam, under an Islamic theocracy, is much worse than being an infidel.
I have a soft spot for pre-Islamic Iranian culture, although I don’t have a lot of primary sources on Zoroastrianism.
I considered the faith to be equally valid to the Judaeo-Christian spectrum as well. Perhaps Zoroaster was to be the Moses of the Indo-Europeans for YHWH/Ohrmazd in a sense. To enlighten the people from Paganism.
My biggest hope is that one day a complete text of the Avesta will be discovered like the Dead Sea Scrolls. I find it very sad that the faith’s scriptures are only fragments of its true splendor.