They changed his name to make him more appealing to western audiences. Stafy sounds engrish so they charged it to Starfy to sound more appealing.

that's late news. That's been a complaiment sunce starfy as announced

This was marred by grammatical error.

But as for this topic yea, the name has been slightly changed.

Why didn't they just call it "Legend of Stafy" like it says in the Superstar Saga pic? Stafy is kinder to the tongue than Starfy anyway :/

Ah well who cares, those cameos in Brawl and M&L were from before an actual game starring the character was released. They just went with the Japanese name then, and altered it sightly to make it more suited so Western audiences, most likely, when the actual Starfy game came out.

These things happen. Link's nemesis had come to be known as both 'Gannon' and 'Ganon' before being called 'Ganondorf' too, it's just the way things go.

Stafy is the actual Japanese name, probably spelled "su-taa-fii" or something similar to that. Starfy is the name "translated", a process they probably didn't care enough to go through when making Mario and Luigi or Brawl.