Ana: While I am in favour of voice coaches for those who need them or just want to improve their technique, I'd have to go along with the first part of PoppaGator's statement.
You cannot teach Tradition. By taking up the song, you become part of the Tradition.
I can only speak for myself since my whole career has been spent as a Soloist with minimal skills on the musical instruments I play and just the occasional venture into groups who were temporarily, in need of a singer.
I take a song, listen to it a few times, discard the album and then practise the song until I know it. In time, my version will be at least, slightly different.

Andy M. Stewart would be the most obvious example here. My wife loves him. He lilts his way through Traditional songs to the point that it can become difficult to decipher the tune. That's his rendering of a Tradional song and is no less Traditional than Callum Kenedy's.
However, if you were to take that same song and sing it, note for note, the same as Mr. Stewart, I'd have to consider that to be your version of an Andy M. Stewart number.
I know what it is that you're looking for but in my opinion if you sing the Tradional song in a manner that comes naturally to you then you are singing in the Tradional manner.
No?