Yes I agree with all your points Kalosyni. I probably am remembering that clip from Jefferson, but I am also thinking that he himself probably picked it up somewhere, perhaps in Cicero or Diogenes Laertius. It's pretty clear that the term appears in a Cyreniac context, and probably the main question is whether there is any evidence that Epicurus or the Epicureans wrote that they agreed with it. I haven't had time to search in Lucretius - let me make a quick check....
Nothing direct so far, but:
Book 2
[408] Lastly, all things good or bad to the senses in their touch fight thus with one another, because they are built up of bodies of different shape; lest by chance you may think that the harsh shuddering sound of the squeaking saw is made of particles as smooth as are the melodies of music which players awake, shaping the notes as their fingers move nimbly over the strings; nor again, must you think that first-beginnings of like shape pierce into men’s nostrils, when noisome carcasses are roasting, and when the stage is freshly sprinkled with Cilician saffron, and the altar hard by is breathing the scent of Arabian incense; nor must you suppose that the pleasant colours of things, which can feed our eyes, are made of seeds like those which prick the pupil and constrain us to tears, or look dreadful and loathly in their hideous aspect.
Book 5
[1379] But imitating with the mouth the liquid notes of birds came long before men were able to sing in melody right through smooth songs and please the ear. And the whistling of the zephyr through the hollows of reeds first taught the men of the countryside to breathe into hollowed hemlock-stalks. Then little by little they learned the sweet lament, which the pipe pours forth, stopped by the players’ fingers, the pipe invented amid the pathless woods and forests and glades, among the desolate haunts of shepherds, and the divine places of their rest.