There is a very reasonable in universe reason why Goofy changes his name. In the movie Who Framed Roger Rabbit Eddie Valiant has a newspaper clipping of an old case that states that Goofy was cleared of Spy Charges. Goofy may witnessed something bad so he would have to go into witness protection. Either he failed to realize that includes moving to a new location and a new life, or he keeps his job as an Actor while changing his identity and location every few years.
…….holy shit