Good for you, Julie: The verses must be organic enough to be a part of the song, and if you sing them that way, I'm sure that most people hear them that way. This is kinda fuzzy territory here... just as you could do a thread about the "Last Folk Song" (you can't write a folk song anymore) you could argue that the time of being able to add verses ended somewhere the other side of the folk revival.But, as someone once said, "The song is the thing." If you have expanded on the song, respecting the original, that seems very much in keeping with the folk tradition.
How traditional of you.
Jerry