Flora was not an uncommon name, particularly in ballads; there's no reason to imagine any connection with the famous one.  Two sets of the song Calach and Pavane quote appear in volume 1 of The Greig-Duncan Folk Song Collection (1981); both seem to be derived from broadsides, and the first, c.1850, has a tune.  It's the first time I've seen the Campbells described as English, mind...