Tom ,if I might refer to your last paragraph,of your first post with reference to style,this is something Comhaltas are attempting to do,I dont think they get it entirely right,but by providing examinations,in the same way that classical music boards provide, in which styles of singing/ Instrumental,styles of ornamentation are studied,and learned about.,people can get an idea of traditional styles.
fortunately we also have many recordings, some of them made by Peter Kennedy[hewas the only man to record thesuperb fiddler NealyBoyle]of these singers/instrumentalists for which I am very grateful.PeterKennedy ,for all his faults collected a vast amount of material,and issued traditional recordings,which I havefound useful.