There's no cheats, but there's a hacking tool called FFXED which can modify your stats and such.
Yes.
If your talking about the codes for things like murasame and godhand and the rest you have to go to the airship and chose to input a code.
Yu Yevon.
Final Fantasy Sonic X is just the name of an online game based on Sonic but with a battle style similar to Final Fantasy's. Check out the related link to try out the sixth episode of this free online...