User blog comment:Zolnir/Cinder Has Two Semblances/Auras/Souls/@comment-3257939-20140523030755

Sorry to break your theory but the fact that she has two colors of aura or can create that flashy thing from her dress and her eyes at the same thing doesn't mean she has two souls:

Pyrrha is the proof. She is capable of changing the color of her aura depending on the type of aura she's using. Red is her original color but her semblance is black colored.