Distinctive means that the textual or melodic variants in question have an unmistakable resemblance that denotes a common ancestry.

Long-established means that the manner of performance in question is generations older than the oldest extant version. In my mind this extant version would likely be a recording since performance is a very fleeting thing unless preserved in that medium.

Texts are a double edged sword when it comes to "long-established manner of performance." In some cases, they can be extremely helpful and can fill in some important missing blanks. In other cases not so much because the publication of a text can too easily alter the manner of performance in a way that breaks the chain. That's where the person to person thing comes in.

Very well worded Lighter. I accept that.