The Nicene creed from 325, 381 holds that the incarnation was before creation. Of course co-eternal is true from that point on. the procession of the Holy spirit from the father was always true. The Father's person is the Holy Spirit.
No. None of the councils or creeds or fathers ever said such a thing.
The Father's person is the Holy Spirit.
That's heresy, either a form of Sabellianism or Monarchianism.
-A8
No, you are confused the eternal begetting of the Son from the Father is not His begetting of the Virgin through the Holy Spirit.
Anything 'from some point on' is not eternal in the sense that God is eternal. The Fathers make a distinction between eternity, which is proper to God, Father, Son and Holy Spirit, and to God alone, and the aeon, the one-sided eternity that beings created with the intent that they be permanent--the angels and Man.
If you don't want to use the technical term 'the aeon' to make the distinction, then one can English the distinction with the phrase 'from eternity', useful only in theology, and let eternity mean what you have mistakenly taken it to mean.
Nor is the Father's person the Holy Spirit. The One God is tripersonal, three hypostases--the Father, the Son and the Holy Spirit--one ousia.