Dorothy is the psychologically integrated self and therefore the least interesting. The Wizard is a chameleon and therefore a disintegrated self. The trio of Dorothy's co-adventurers are the more easily understandable and have the more interesting pathology. Even though the trio eventually recognized the Wizard was a humbug they clung to the crutch he offered. Or was he a humbug? The analyst returns to you a little of your own juices and calls it treatment. He can't give you what you already have. He just puts a knob on the door to yourself.
Did the Lion recognize his courage other than by the faith in a placebo, a draft of courage he was given, fished up by the Wizard? He didn't know he always had courage. He found it had always been there when it was apparent to him the Wizard was not a whiz. Did the Scarecrow suddenly get his brains from a magical source in Oz? He didn't twig to the fact that he was always smart until the Wizard took his head off and inserted pins and needles mixed in bran. Being sharp with a bit more bran new brain he realized he was always that way. That's when we realize what we seek was already there in spades and we just needed a topping up of the same stuff. Did the Tinman get a heart other than a silk valentine from the Cardiowizard inserting it with a can opener into the chest? Nonsense! The Tinman always had a heart , but his heart was in the right place, his head. He just didn't recognize it. None of this trio realized their gifts till they combined their brains ,courage and love with helping Dorothy to get home.
Who knows what is below the topsoil of Frank Baum's masterpiece. On the surface it seems an exploration of the human condition. There are two bookends to every story, the author and the intent, the reader and the understanding. What he said and what I heard. They may not be the same. It may not be important that they are the same! Just look where the roots live.