Good question, Daniel.

The "fancibles" bit isn't too difficult to explain:

1. In the old version, the mother has given the narrator a list of odds and ends (needles, threads, buttons etc. at a guess) and wants to be sure he brings them back.

2. In the "modern" version, the song is loaded with sexual innuendo and the "fancibles" are stray women!

It's hard to imagine singing the older version - some parts fit awkwardly to the tune and, as you say, the story is confused. The "modern" version simply leaves gaps for the overactive imagination to fill! Much more satisfying!

Regards