Those are good.
I like Pericles.
You are spelling Archimedes incorrectly (at least if you're going for the standard translation).
Phobos (which means "fear") is "the embodiment of fear and horror in Greek mythology" according to Wikipedia. Not sure if I'd want to name a dog after fear and horror.
I guess you said no other suggestions, but there also were some other Greek & Persian military names I liked as dog names -- less famous than Pericles (which you could shorten to Peri) but just as much fun: Miltiades (or Milt, for short) and Bubares (or Boo).
Links below to history on these gentlemen.