I dont think the kids would over analyze the movie, such as if the wizard being revealed as an ordinary person stating each character already possessed, in themselves, the traits they were seeking, as being an atheistic metaphor.
And Dorothy does wear a skirt, but does show her elbows..
So…that being said..
They will probably be captivated by the movie and will thoroughly enjoy the Lion, Tin Man, and Scare Crow, as well as the songs.
Now, the other question is: Colorized or Black and White version?