I've now read the Harwood book, apart from the appendices, but it has left me pretty confused, partly because a lot of the information seems very peripheral, if relevant at all, such as the words of some entirely unrelated songs. Maybe I'll do better if I read it again.

Harwood does offer one suggestion for making sense of the "Let her go" verse, but I can't tell how seriously. He points out that the clothing requested for the funeral was characteristic of two types of men, gamblers and pimps. So he combines them: "Our gambling man is a pimp. His baby, so sweet, so pale, and so dead, was one of his girls. He, of course, is the best of pimps. He cares for his women. He keeps them off the streets. And though they might search far and wide, they'll never find a sweeter pimp than he".

I can see at most three common features between the St James Infirmary / Gambler's Blues family and the Unfortunate Rake family, and two of those are tenuous. The only strong one is the funeral requests. But we are quite familiar with floating verses that crop up in songs that are otherwise distinct. Drawing the line is tricky with songs that consist mostly of such, but (for example) we don't say that every song with a verse about a rose entwining with a briar must really be a version of Barbara Allen. So the description of the desired funeral could be borrowed and re-used in a song that is otherwise entirely separate, not a descendant.

The "St James" name seems to belong in only a very few "Unfortunate Rake" versions, and again could have been borrowed.

And there is the frame, where someone (the singer) goes somewhere (a bar room, an infirmary, The Royal Albion, The streets of Laredo / etc) and sees a son/daughter/friend/sweetheart either dead or dying.

As I said, I'm still confused!

It would be helpful to have the words of enough versions together in one place. A few days ago Brian said "what we really need is Richie Matteson on the case." There are a few posts from Guest Richie way up thread.