"You now agree that Jesus did not pass through the birth canal?
Scripturally unsupportable."
No; I agree the birth was painless and perhaps by some miracle The Theotokos remained "intact", though I must say I have never ever been told that was a dogma of Orthodoxy.
A woman does not have to have an intact hymen to be a virgin. Young girls lose they intact hymen through horse-riding, other athletic endeavors, medical necessity, etc.
Do you agree that a young girl who has never had sex should be considered promiscuous if her hymen is ruptured?
Perpetual virginity is the dogma of the Church of the Seven councils, specifically Chalcedon, as you yourself quoted. The physiological details are not defined by the Catholic Church either, but it is a common and logical opinion taught by the Catholic doctors that Our Lady remained miraculously intact in the physiological sense and was spared the birth pains, as well as remained virgin in the social sense. Jo, please correct if I am wrong.