[1] Generically so, but also, on occasion, used of the kwmiko/s par excellence, Aristophanes (alpha 3932): for this see e.g. alpha 4196 (= sigma 525), pi 463.
[2] This phrase as a whole comes from Lucian, How to Write History 4. Note LSJ s.v.: 'used of mute characters on the stage'. Its noun, dorufo/rhma, was applied several times by Plutarch (e.g. Alexander 77.7) to alpha 3874, Philip Arrhidaeus, the ineffectual elder son of Philip II of Macedon (and half-brother of Alexander the Great).