I should note that regarding Liza Wells - the songs in the repertoire of Val Turton are mainly popular 19th century songs from America, England and Scotland.
Liza Wells has always sounded like a broadside to me but I've never been able to track it down. There are a few American murders that might fit the story - one has the girl's name as "Betsy" but the links seem a bit vague.
Liza Wells sounds rather like a "goodnight ballad" without the hanging - something Jemmy Catnach - the famous broadside printer - might have come up with on a slow day when there was no genuine news. That's my read on it, but it's just a theory. Joy