When PriaposLovs gets back (where IS he, anyway? He's been gone too long.) he'll no doubt be able to give you the Greek etymology on "Pyre" and "Pythos".
I would think that "Pythos" may have something to do with the Oracle of Delphi, though, as I know the priestess there in ancient times was called the "Pythia". And then there were the Pythian Games celebrated there every four years (much like the Olympic Games), only these were in honor of the god Apollo.
And Latin words for "fire" are: "ignis", "flamma", and "incendium".