Yeah, none of these texts touch the relevant point I made. So here is what you have to think about. For a Platonist, how is a soul individuated from the All Soul? This comes about via embodiment, which is discussed in part in Plotinus’ Ennead 4 with respect to the fall of soul to body. As I already noted, Augustine holds to the principle that the penalty of death is justly applied to those that sin. Infants die and so therefore they must have sinned. If they die and they didn’t sin, the penalty of death would be unjust on God’s part, but that is impossible. Hence infants sinned. How and when did they sin then? They sinned when they were the one soul or person of Adam. Now that individuation of soul has taken place that guilt and sentence of death still accrues to them, but the mode of its existence is no longer strictly personal. Why? Because they have been individuated from Adam and are now a distinct new person. They did not cease to be a person though in this process. Hence the sin exists in them in a kind of metaphysical limbo between the categories of person and nature. And the reason for this is due to the fact that Augustine is working even at a very late date, with a Platonic conception of soul and this does not admit of a distinction between person and nature. This is why in Contra Julian his account has to transgress the person/nature distinction to carry through on his argument in the face of Julian’s criticism. So it appears to me what you are getting hung up on is Augustine’s discussions post individuation of soul and ignoring the fact that the sin was genuinely that of the infants when they were the person of Adam. The sin does not exist in them as something they did now as a discrete act from a discrete person from Adam, true enough, which is what Augustine is denying when he speaks of original sin as a personal sin of theirs. So if the guilt was not theirs then the sinful act of Adam was not theirs either, in which case they would not die, but they do die, ergo their sinful act and Adam's are one and the same because they were the person of Adam at one point in the past. Again, the principle that Augustine adheres to from his debates with the Manicehans all the way through to Julian is that only those that sin suffer the penalty of death. To say that infants did not sin therefore is to entail that the penalty is unjustly applied to them by God. Part of the problem here for Augustine is that along Platonic lines he is thinking of the person as the soul, which won't work with an appropriately expressed Christology. It is one reason why Augustine tends to speak and write of Christ as the result of the union between God the Word and "the man" due to an influence from Origen as you can see below. energeticprocession.wordpres…

On Ortlund's remarks about saintly invocation being post 2nd/3rd century, can Ortlund show Augustinian predestinarianism prior to the late fourth/early fifth century? How about Limited Atonement? No, he can't. Even Augustine strained to do the former when pressed. On the other hand, baptismal regeneration can be shown to have existed in the time frame Ortlund denotes, yet this doesn't apparently move the ball for him. So, it wouldn't matter if we found saintly invocation expressly exhibited in the first or second centuries. Ortlund would just dismiss it out of hand as well and retreat to his own judgment as to what scripture teaches. That is, he will only be bound by his own reading of Scripture.