Raphael did not leave any written notes who is who in this fresco! All are speculations.
However, Aristotle, Plato Socrates were painted by him similar with their busts. Raphael had info for these philosophers busts, but he had no info for Epicurus bust, but at the same time in his fresco Raphael has painted a person that is similar with the bust of Epicurus. Raphael had info for Socrates bust, but he had no info for the latest philosophical mainstreams that were prevailed in Athens and in Rome, and these were Epicurean philosophy and stoicism. Interesting eh?