The Child ballads are a false lead. They have no direct connection with practicing polytheists.
I advise the founder of the thread to re-examine the presuppositions on which the inquiry rests. What is meant by "pagan" "magical" "folk" or "Earth" religions? And why should these be considered to have "primarily oral tradition?" Counterexamples spring easily to mind. The Brahmins of India are both "pagan" and literate. Much brahmanical lore is now passed down in books. On the other hand, the literate phase of brahmanism may be a late development. Would MudPuppy consider the Brahmans to have been "pagan" before the Vedas were written down, and "non-pagan" afterward?
Again I encourage MudPuppy to consult the works of Ronald Hutton. Carlo Ginzberg's works may be useful, but I can't say for certain because I have not yet read any of them. From what I know, he is a careful scholar but his work is difficult. I also encourage MudPuppy to AVOID the following authors: Sir James Frazer, Marija Gimbutas, Robert Graves, and Margaret Murray.