Base on my theory, Paimon is the Heavenly Principles.
I have a similar theory. To put it shortly: Paimon was once a member of Celestia, but after The Cataclysm she fought the other members, and they turned her into the floating squeaky-voiced pipsqueak that we all know and love to call “Emergency Food” and then kicked her out for being nice to those beneath her instead of quietly lording her power over her lessers like they were. Yes, they did that to her because she was NICE.