Have you asked an Orthodox Jew who the Holy Spirit is? We have a member who is answering questions in the Judaism Forum. So why don't we ask him your question about the Holy Spirit?
You posted that God, the angels, and etc. are spirit, so what you are telling me is that God who is spirit has a seperate and independent spirit? Do you know how ludicrous this sounds?
Since you want to compare the seven spirits of God to Zoroastrian belief then why ignore the obvious comparison between your concept of Mary and Isis/Horus? All Catholicism had to do was rename pagan Isis temples that had images of Isis holding her infant son Horus and they had churches named the immaculate conception.
The Bible convinced me the Trinity is a false doctrine for the reasons I have posted, reasons that all Trinitarians either avoid and try to interpret away. Why would Muslims believe that a merciful god would tell them to lie, extort, and murder? Because they are ingrained with a belief from the cradle forward and never question what they are taught. In my discussions with Trinitarians most of them simply parrot what can be found in commentary after commentary most of which I read years ago along with all the other interpretations of God's word that back up the doctrine of the Trinity.
Jehova's Witnesses are just as wrong as Catholicism is.