John
I see your dilemma and wish you luck in finding evidence. If that evidence is not forthcoming you might want to fall back on probabilities. If we are to believe the collectors and Child, c1800 the ballads were very much alive in Scotland at that time, even allowing for a substantial percentage of forgeries and literary interference. It is therefore extremely likely that any waves of migrants from Scotland and N Ireland/Sc would have a store of ballads in their heads, and using the old 'Scots abroad' maxim they would have been very keen to keep these artefacts alive.

Brian,
I have posted on Mudcat before my feelings on Earl Brand and the Bold Dragoon. They simply have a couple of lines in common and no other relationship. The desire to connect the two, somewhat ironically in light of what you say, was due to American collectors in the first half of the 20th century being desirous of including Child ballads in their collections and grasping at straws. I have mentioned this to Steve and I can't remember what he did about it. I have an up-to-date Access spreadsheet of the Index but unfortunately haven't currently got Access on my new computer. I'll be seeing Steve tomorrow night when he gets his EFDSS Gold Badge and will ask him to check. Certainly The Bold Dragoon and Earl Brand should have separate numbers.