Maybe she should be a Warrior of the Light, like Jay. Jay basically had the power of the Outerverse pumped into his spirit, and as such became an avatar of the Outerverse itself. It's still his own spirit, but the Outerverse, for a time, took over his spirit and spoke through it, shared it if you will. While Jay's "Warrior of the Light" stage is dormant until he activates it (he learned to control the dimensional energy within his spirit I guess), maybe it's constantly active in this child? The spirit would still be her own, but she's an avatar of the Outerverse.