The ECF are univocal. If they weren’t, they would not be ECF.
But the hypothesis of Basilides says that the soul, having sinned before in another life, endures punishment in this–the elect soul with honour by martyrdom, the other purged by appropriate punishment. How can this be true, when the confessing and suffering punishment or not depends on ourselves? For in the case of the man who shall deny, Providence, as held by Basilides, is done away with. I will ask him, then, in the case of a confessor who has been arrested, whether he will confess and be punished in virtue of Providence or not? For in the case of denying he will not be punished. But if, for the sake of escaping and evading the necessity of punishing such an one, he shall say that the destruction of those who shall deny is of Providence, he will be a martyr against his will. And how any more is it the case, that there is laid up in heaven the very glorious recompense to him who has witnessed, for his witnessing? If Providence did not permit the sinner to get the length of sinning, it is unjust in both cases; both in not rescuing the man who is dragged to punishment for righteousness’ sake, and in having rescued him who wished to do wrong, he having done it as far as volition was concerned, but [Providence] having prevented the deed, and unjustly favoured the sinner. And how impious, in deifying the devil, and in daring to call the Lord a sinful man! For the devil tempting us, knowing what we are, but not knowing if we will hold out, but wishing to dislodge us from the faith, attempts also to bring us into subjection to himself…Wherefore the Lord was not prohibited from this sanctification of ours. if, then, one of them were to say, in reply, that the martyr is punished for sins committed before this embodying, and that he will again reap the fruit of his conduct in this life, for that such are the arrangements of the [divine administration], we shall ask him if the retribution takes place by Providence. For if it be not of the divine administration, the economy of expiations is gone, and their hypothesis falls to the ground; but if expiations are by Providence, punishments are by Providence too. But Providence, although it begins, so to speak, to move with the Ruler, yet is implanted in substances along with their origin by the God of the universe. Such being the case, they must confess either that punishmerit is not just, and those who condemn and persecute the martyrs do right, or that persecutions even are wrought by the will of God. (Clement, 1888, book IV, chapter XII)
Is the most cogent argument. A belief in a pre-existence justifies social injustice. Which Mormonism, in its traditional form, does in spades.
There is also this, which shows that the best were consistent in their decision.
But their transmigration from body to body we may overthrow by this circumstance, that should remember not at all any of what was before. For if they were sent out with this view, that they might pass through every kind of working, they ought to remember the things that were done before, in order to fulfill what was wanting, and not toil in wretchedness, always wallowing in the same things without intermission. For the admixture of body could not entirely blot out all memory and contemplation of what they had before: especially, such being the purpose of their coming…
…But those who deserve punishment will go away into the same, having also themselves their own souls also, and their very own spirits, wherein they have pleased God. But those who deserve punishment will go away into the same, having also themselves their own souls and their own bodies, wherein they fell away form the grace of God. And both sorts will cease from propagating any more, and from being propagated; from marrying and being married: that the race of mankind, completed to the just proportion according to God’s predestination, may preserve the harmony framed by the Father. ( Keble, trans., 1872, p. 195-198)