I know the Orthodox reject the Augustinian view, but I thought you chaps had something similar; ancestral sin, isn't it?
Ancestral sin does not make people guilty of other people's sins (see Ezek. 18). It is the ancestral sin that caused inherited death, inherited mortality, not inherited sin. We are born mortal, subject to death, and born with the knowledge of good and evil, a knowledge that God wanted to forbid to Adam and Eve. God told Adam and Eve not to eat of the tree of the knowledge of good and evil, but they both ate of the wrong tree. If they had abstained from eating of this tree, God could possibly have rewarded them for their faithfulness, and given them access to the Tree of Life, and they would have become immortal.
This did not happen. Knowing this, Christ is predestined and has always existed, from the beginning He was there with God the Father and God the Holy Spirit. These three Persons, Father, Son, and Holy Spirit, have always existed, and will always exist, for they are One God.
The only God (Isa. 44:6).