I too enjoy looking for these hidden meanings. I've recently re-acquired a new copy of Folklore in the English and Scottish Popular Ballads by Lowry Charles Wimberly – a book I had owned but loaned to someone in the late 60s and not seen since. It has some fascinating flights of fancy about hidden references to magic and myth in some of the Child ballads.

As for the counting down chorus though – I'm not convinced. Whilst the reversal of the Lord's Prayer is an oft-quoted part of a satanic mass, there is little evidence that I'm aware of that this ritual was ever practiced by "ordinary folk", rather than 18th Century drunken "intellectuals". I think you would need to look to folk-magic, the use of herbs such as practiced by wise-women/cunning-men and belief in an otherworld of spirits, rather than the high magic spells and incantations of the Crowleys and Dennis Wheatleys, to find examples embedded in folk song. Perhaps the mediaeval interest in riddles and tongue-twisters is a more profitable source of explanation for some of the more obscure choruses