There are so many points raised in here I will try to touch up on them…
First the baptism we are talking about is the Christian baptism not the baptism of St. John the Forerunner. The Mystery of Baptism cleanses us from the ancestral sin, gives us illumination and makes us the part of the body of Christ. It is not repeatable.
The Theotokos on the annunciation she was filled with the Sanctifying Grace of the Holy Spirit, who Cleansed her of the ancestral sin, and gave her the power to receive and conceive the Eternal Word in flesh. The fullness of Divinity became flesh in her womb!!! The Father found her to be Worthy and Chose her of all the creation to be the Mother of His Only Begotten Son in flesh. We know all the prophesies about her and her archetypes of the Law found fulfillment in the New Eve, the Living Temple of the Holy Spirit, the Holy of Holies , she who without seed brought forth God the Word in Flesh. We know what the Angel said to her at the annunciation, Rejoice O Full of Grace the Lord is With Thee! Who else among creation has heard such a greeting in the Spirit? Or when the angel said to her “The angel answered, "The Holy Spirit will come upon you, and the power of the Most High will overshadow you. So the holy one to be born will be called the Son of God” or the Holy Spirit Himself inspiring l humans both in the womb and outside of it who were favored enough to hear her voice to praise her in the Spirit, “0where she entered Zechariah’s home and greeted Elizabeth. 41When Elizabeth heard Mary’s greeting, the baby leaped in her womb, and Elizabeth was filled with the Holy Spirit. 42In a loud voice she exclaimed: “Blessed are you among women, and blessed is the child you will bear! 43But why am I so favored, that the mother of my Lord should come to me? 44As soon as the sound of your greeting reached my ears, the baby in my womb leaped for joy. 45blessed is she who has believed that what the Lord has said to her will be accomplished!” Luke 1:40-45
Why was this? Because it was the fulfillment of the Law and the Prophets, the sun of righteousness has come! The Light of our Salvation has arrived in the house of David the Eternal Living Temple established, the perfect union of God and Man Accomplished in her that willingly gave him our humanity as He in turn gave us His Divinity in a perfect and everlasting union that has risen up humanity to heights of Glory indescribable! By His will and by the will of His Father and The Holy Spirit along with the will of the blessed virgin, He became Perfect Man in all things except sin, as he is born of her who has been made all pure by the Holy Spirit Himself! He took pure flesh of her pure flesh, pure soul of her pure soul and became one of us.
What is lacking in her that she who is full of Grace that she brought forth the Second Person of the Holy Trinity in Flesh needed a baptism of water for? She that carried the fullness of the Divinity Himself and became the Living Temple of the Spirit, the Holy of Holies, the Living Ark of the Covenant, who would dare to say that she needed a second baptism and that of water when the very Fire of Divinity dwelled in her womb and she gave birth to Him in Flesh?!
If the Lord was baptized by John it is not because he needed it, but because we benefited from it, because it was part of His salvific work, to sanctify the waters of the world, to enable us to receive the Holy Spirit. It was not to obey the law as the baptism of John has nothing to do with the law but everything to do the prophecy of the Theophany. When the Holy Spirit came upon Him it was not because the Holy Spirit was separated from Him before.
If the Lord kept the Mosaic Law, it was to fulfill them and perfect them; it was not because he was bound under them. He was the Giver of the Law and its perfection. He fulfilled all righteousness for our sake.
His mother who kept the law and the ritual cleanliness did so not because the Temple who holds the ark was holier than her the Living Temple of the Fullness of the Divinity in Fleshed in her, or that she somehow became unclean by giving Birth to the Holy One of Israel. God Forbid we would say such a thing! The restored Humanity is the full humanity as it was meant to be in the Theotokos not only was she restored to the state of humanity before the fall but elevated even above because the New Eve is truly the Mother of the Living! The Curse of Eve was loosened by her when she gave Birth to the Word in Flesh! Both virginity and Birth became sanctified because she gave birth to the Word Incarnate while remaining a Virgin. She is ever- virgin,” qideme welid, gize welid , dihere welid/ Virgin before birth, Virgin during birth, Virgin after birth/according to the Prophecy. The entire point of the preparation through the Law and separation of the people of Israel was in preparation and preservation of her that will be worthy to give Birth to the Son of God in flesh .Isaiah 1:9 “Except the Lord of hosts had left us seed, we had been as Sodom, and we should have been like to Gomorrah.” We all know what happened to humanity because of the disobedience of the first Adam and the first Eve. Let us by the help of the Spirit contemplate then, what is accomplished by the Incarnation, through the Second Adam and the Second Eve.
To keep it simple, the Theotokos did not need the baptism of repentance by John who was filled by the Spirit upon hearing her voice while he was still in the womb of his mother Elizabeth. We have seen why the Lord got baptized by John in the Theophany, not out of need for himself but for our sake and in fulfilling the prophecy. Just like Christ did not lack the Holy Spirit before when it came to rest upon him in a form of a Dove, the coming of the Spirit on the Theotokos on Pentecost is not because she needed to be re baptized by the spirit in order to be cleansed from the ancestral sin and become the body of Christ because that already has happened as it is the very thing why we are all baptized for. She has already had the fullness of Grace from the fullness of her Son’s Graces. She is the only one who bore the Word in Flesh, her glory beyond compare from all creation; she has become higher than all creation in that very second of the Incarnation no one created can ever supersede her in purity, honor and glory. On Pentecost the Spirit Came to establish the Church and give witness to the Son the Beloved of the Father and make all things new through the Son for the Glory of the Father. The Apostles got baptized by the fire of the Spirit and received His Chrism according to their ability and they became the members of the Body of Christ. For them it was necessary to receive this power that sanctified, illumined, strengthened them and sealed their communion with the Trinity as members of the body of Christ. Even if Pentecost did not happen she already had acquired the fullness of the Grace of the Spirit in her on the annunciation. we must then keep in mind that on Pentecost It’s not as if this is the First time that the Holy Spirit has come upon her, what are we claiming happened in and through the Incarnation? Where we hear everyone from heaven among the Angeles and earth among the saints and the prophets all blessing her in the Spirit and the Spirit Himself testifying on her behalf. Verses that of the awaiting till Pentecost to sanctify her, who bore the Holy One of Israel, where is this new sentiment coming from? Certainly not from the Orthodox Fathers, who all had the same understanding of the law and the prophets who spoke about her, whom she is the archetype of, and who all had the same love that was in her son for her, and who all have tasted the sweetness of her motherly love and who stood in awe forever contemplating the indescribable glory of the Mystery that was done in her. but even if it was a personal speculation of sorts by what ground do we deny or reject what happened on the Incarnation, as insufficient to be sanctifying, illuminating and unifying Grace of the Holy Spirit, by whose Power it happened, and what it mean to her and to the entire humanity in the fulfillment of the law and the prophets in her through her son and her obedience?
“Glorious things are said of thee, O city of God” Psalm 87:3
Sorry for the long post, I will be quite busy in the next few days, but I will try to reply as soon as I can.