Dick,
The 54 definition is ONE very good definition that would be easily accepted and recognised by most of us here. Origins are irrelevant so there's no point bleating on about Music Hall. Walter's songs learnt from his own community orally all fit the definition perfectly. The word 'traditional' can be applied to a multitude of things. Anything that has a continuous past has its own traditions. If you use the word 'folk' in the same context as 'folklore' then its meaning is quite clear. Like most words in the English language the word 'folk' has come to have a variety of meanings when applied to music. The 54 definition is just one of them.