Celeste is a softly pretty and somewhat quaint name with heavenly overtones, which kids might associate with Queen Celeste of Babar's elephant kingdom. She's a light and lovely choice that's finally getting noticed.
Celeste has been in the Top 1000 every year since 1880, and now ranks at Number 467. Best known modern Celeste is Oscar-winning actress Celeste Holm.
If you want a more unusual variation, consider Celestine, Celestia -- or even Celestial.