About the Hanukkah festival and the legend of the oil miracle: It seems to me that the teaching we must convey to youngsters and adults regarding the miracle of the oil is that we do not and must not confuse origins with validity, meaning contemporary authenticity. Not if we identify as progressive Jews.
Christmas and Hanukkah (even if the latter was Sukkot delayed) were originally winter solstice, light reawakening, sun-returning, sympathetic magic related commemorations and celebrations. But what Judaism and Christianity did with that reality is what counts. For Christians, the birth of a Savior born into this world to die in atonement for our/original sin. My friends who are Catholic priests and Protestant ministers tell me that has not changed. For Jews, the festival of lights developed into a celebration of religious liberty, interpreted to mean that Jews need not and must not be swallowed up by the majority religion/culture. We should teach that regardless of origins, today we understand the two different festivals of light accordingly.
There are examples without end of the diametric of origins and validity which we should be teaching, from the silly to the sublime: breaking the glass at a wedding originally was intended for frightening away evil spirits. Today we attach another meaning to this entirely. A chag was once a dance. The religions of all the peoples of the world have common astral origins - even recent ones. Yisrael originally meant "Saturn - Moloch - will protect." Later it was taken to mean "wrestling with God," or with "the ultimates." An adult person is not the same as when a newborn infant and the like. If we begin this lesson with the baby and the adult example, even the little kids get it. After all, we do teach that the transition or development of meaning(s) over time is what progressive Judaism is all about.
Concerning "the problem of the birth of religion and of monotheism in particular," Velikovsky wrote, "investigation should be made into why and how the Jewish people, who had the same experiences as other peoples and started with an astral-religion like rest of the nations, early cast off astral deities and forbade the worship of images." (Worlds in Collision).