I appreciate that you added repentance for our sins, re: “Postsalvation sin. Again, Repentance and confession.”
I think you could say one does not really occur without the other; but, for this discussion, wouldn’t your theology allow for a saved person without repentance?
Saved as in possessing a regenerated human spirit and a new man in him, which has been sealed by God the Holy Spirit.
We still have a scarred soul (nous) which can effect our heart in our behavior.
There is now a portion of us which is veritable, namely that which God has breathed into us in our regenerate spirit. That is the starting point by which He is able to slowly cleanse the rest of us.
If we fall out of fellowship, we still have the human spirit, but we become tainted in our perspective. Until we turn back to Him, we don’t have a veritable resource upon which to rely, because we now approach Him from the perspective of guilt, instead of fellowship. When we confess our sins to Him, we are performing an action of the heart, a part of the soul, which now faces back to Him and He is one that forgives, because He is free to forgive and by His grace forgives us through faith in Christ and His work on the Cross.
Presalvation repentance? No.
Postsalvation repentance? Yes,..namely the sin unto death if the believer out of fellowship continues down a path such that all opportunities for God the Holy Spirit to perform a good work in us are all burnt up, so to speak.
Since God does nothing that is good for nothingness, He will not continue to indwell us, if all instances in His Plan have been denied to the point where we are no longer effectual and refuse to return to Him.
It is also possible for believers to fall out of fellowship, remain saved, but fail to walk the walk. Divine discipline manifests He still loves us in these situations. Not all adversity is from His discipline, but some discipline is rendered to get our attention for us to return to Him.
A good example is Paul and his many stays in prison when Paul attempted to return to Jerusalem to teach the Pharisees and Jews, when in God's Plan, Paul was to be an Apostle to the Gentiles and go to Rome.