It may be that we are saying the same thing here, HD. The Fathers did not teach that the soul was by its nature immortal (and certainly not eternal and pre-existent). You’ve cited to +Iraeneus. Here’s what he said:
“Christ Jesus, our Lord, and God, and Saviour, and King...may, in the exercise of His grace, confer immortality on the righteous, and holy, and those who have kept His commandments.”
No natural immortality there, HD. Note who gets immortality. Most of the Fathers spoke to this and quite clearly. Dr. Boyce’s article, at least insofar as he speaks of immortality of the soul, isn’t even remotely in accord with what the Fathers taught, but then again, the joyous (for some) prospect of truly eternal and unspeakable torment for the innocent non-elect couldn’t be enjoyed if the souls of the wicked are not immortal.
"Souls can be recognised in the separate state, and are immortal although they once had a beginning".
It is rather difficult to argue that St. Iraeneus isn't saying souls aren't immortal after they are created. Once again, he also states:
Nevertheless they endure, and extend their existence into a long series of ages in accordance with the will of God their Creator; so that He grants them that they should be thus formed at the beginning, and that they should so exist afterwards.
I think Iraeneus if very clear that once God has created a soul, it exists forever.