Well... I regard the term 'Traditional Singer' as an impossibility. The descriptive term is given incorrect emphasis. It cannot describe the person, only the material they choose to sing.

A singer of traditional songs, or a singer in the traditional style, maybe.

Ray's 'Traditionalist' works, though.

Would you speak of a 'Real Ale Drinker' or a 'Drinker of Real Ale', for example? Man eating lion and man eating banana...!!