When handling Ozma in Outsiders from Oz, I realized she was a difficult character to handle. I tried to handle my characters as human characters (even if they weren't human), and realized Ozma is also a fairy princess. As such, she can do magic and may have some powers we haven't seen. (Chapter 10.)
Ozma's history is confusing. The Marvelous Land of Oz has it that she was simply the daughter of the last king of Oz (Pastoria), but in The Tin Woodman of Oz, it is said that she was appointed be the ruler of Oz by Lurline. Jack Snow complicated this continuity by setting Oz becoming a fairyland in Pastoria's reign and she left Ozma as a baby fairy to Pastoria as his adopted daughter.
This would work, except it seems Oz has been magical much longer than shortly before the Wizard's reign, especially since Wicked Witches had time to seize power.
My own personal theory and backstory for Ozma is that Lurline made Oz a fairyland a long time before Ozma's reign. Ozma is Pastoria's daughter, and was only as magical as a person of Oz could be. However, there is an unrecorded chapter in Ozma's life after she was restored to the throne during which she met Lurline, who made her an honorary member of her band and was given some magic power.
This unrecorded chapter of Ozma's story would have to happen before The Tin Woodman of Oz. I'd doubt it happened before Ozma of Oz.
I'm suddenly beginning to wonder how this effects what Mari Ness calls "Ozma fail."