I would go along with Phil on this one - Tradition Berarers is fine by me.
MacColl, back in the mid-sixties suggested that there were many singers who had just caught the tail end of a living tradition, but who had not participated in one (there are plenty of examples here in Ireland, where the singing tradition went on much later than elsewhere in these islands) might be called 'Song Carriers'. That one works for me too.
Revivalist always sounds to me like a religious meeting, but I've never been able to think of an alternative and have always used 'younger singers', but looking in the mirror nowadays - this doesn't work any more.
Jim Carroll