I would only question your naming of Sin and Death as being among the Pauline “principalities and powers.” It seems to me that these fall in a fundamentally different category. The principalities are created realities, of God knows what ontological status, but anyway created and, tragically corrupted. But Sin and Death aren’t created. They are names for the corruption — for Evil — itself. This may seem a theologian’s quibble, and I’m happy to acknowledge that from the ordinary mortal’s point of view these are all powers or systems opposed to God that enslave humans. But it does make a difference. The powers can be — at least eschatologically and in principle — redeemed; Sin and Death, not so.
This is precisely right, and not at all a quibble. (And I knew better! Annoyingly sloppy on my part.)
We don’t really understand the “ontological status” of the Powers: I wrote about some of the complications here. Demons, whom I describe as the agents of the Powers, are equally difficult to fix ontologically, as we may note when we hear “My name is Legion, for we are many” (Mark 5:9).
Moreover, it has not always seemed clear to Christians that angels, demons, and human beings exhaust the categories of sentient creatures. Milton writes darkly of “middle Spirits” whose nature lies “Betwixt the angelical and human kind” (Paradise Lost, Book III). In The Discarded Image C. S. Lewis details the medieval belief in creatures whom he calls longaevi — these are very close to Tolkien’s Elves — whose place in the drama of human salvation is uncertain and debatable. In That Hideous Strength Lewis has one character speculate about the existence of “neutrals” — beings who originally were not concerned with the spiritual warfare that dominates the human world but who are being drawn into that conflict, being compelled to choose a side, as we all ultimately will.
But in the end, this much can be said about all sentient creatures: At the name of Jesus every knee shall bend, in heaven and on earth and under the earth, and every tongue should confess that Jesus Christ is Lord, to the glory of God the Father (Philippians 2:10-11). That includes the Powers, the angels, the demons, the rulers of this world (kosmokratoras), and humans made in the image of God.
But it does not include Sin and Death, which shall be eradicated. That’s the key difference: All powers and rulers, whether in the end redeemed or not, will confess the One Lord who is the Way, the Truth, and the Life. But Sin and Death will be altogether destroyed.