1.   What is the central, core doctrine of the Armenian Apostolic Church?
The Nicene Creed was adopted at the First Council of Nicea (325 AD). About 318 bishops from the whole of Christendom were in attendance, and many of these bishops had been severely persecuted for their faith, even to the threat of death. All but 3 of the 318 bishops put their name to this creed.
The 3 bishops who rejected the Nicene Creed were of the Arian heresy which believes that Jesus Christ was made at some point in time and that Jesus is not of the same substance of God the Father (i.e., the Arian heresy believes that Jesus is truly inferior to God the Father). Every Orthodox and Catholic Church resoundingly reject this heresy.