The trinitarian dogma was fully developed in 4c, so naturally St. Ignatius relies on the Gospel texts alone, which, regarding His divinity, can be read in a variety of ways. This is not a disagreement -- unless you are prepared to say that the Gospels are in disagreement with 1st Nicea. Is is undeveloped doctrine, and continuity of doctirnal development.
authenticity
I will not participate in discussions of authenticity based on which copes of what survived. This approach is waste of time.
called Mary advocata
Mary is sometimes called Advocate today, so again there is no discontinuity in that. I also had to hire a lawyer not long ago, and were I speaking to him in any of many languages other than English, I'd call him advocate, because that is what "advocate" means.
Not just the Gospels, the Epistles and the early Church Fathers as well. The Son is always portrayed as subordinate to the Father.
Mary is sometimes called Advocate today...
The meaning of the term, as used by Irenaeus (i.e. Second Eve advocating for Eve), was that of the Paraclete in Greek. The concept of Mary being the Second Eve is unbiblical; it is an invention of Justin Martyr's.