AFAIK, there are a few japanese forums (from 2008 or so), in the early years of Gen IV, where japanese users refers to Ahiru's Wonderland. Maybe we can't contact Ahiru but one of the users to try to find answers, probably they won't still active but who knows, we might find something more than a japanese Celebi?
Yeah, I also agree, most of them stop caring about Pokémon and some others (most from Ahiru's years) don't even know PPorg exists.
True , the chances to find something in a Stadium GS cart are REALLY low, but I think that is the only way we may get something by ourselves.