I know shiny pokémon can be caught in Pokémon Colosseum. I have a copy of the game and I wanted to hunt for it. Is it possible to get a shiny Ho-oh? I know that lugia is shiny locked in Pokémon XD due to it being a shadow pokémon, however Ho-oh is not a shadow pokémon and it was implemented before the shiny lock on shadow pokémon since shadow pokémon can be shiny in Pokémon Colosseum.
In Pokémon Colosseum, non-Shadow Pokémon obtained in the game (such as the player's starter Espeon or Umbreon and Duking's Plusle) are ensured to be unable to be Shiny.
Unless I'm misunderstanding something here, it seems that a shiny Ho-oh cannot be caught in Colosseum because it is not a Shadow Pokemon. Source