I recently got a Japanese disc of galaxy, but can’t figure out how to turn my American 120 star save to a Japanese one. Thanks for the help in advance

I don’t have too much familiarity with galaxy 2, so sorry if this is a stupid question. Is there a cheat code that could be used to start the game as Luigi, or is that impossible, and if so why?

When first speedrunning this game, is it better to start off with Luigi or Mario?

I have more experience with Mario than Luigi, do you think I will pick up how he controls quick?

Update: If you are looking back on this in the future, choose Luigi. He is more fun to play as, and the tree skip is so much easier