>>43753777That'd probably be right on the money.
I know that, outside of Ho-Oh and Togepi, the Johto Pokemon that premiered in the anime before GSC were random because GF didn't finish most of the designs until the last minute. They weren't even given a full roster of designs until halfway through the third movie's production; also meaning that they had to be planning out Johto even before they knew a ton about the games, which probably explains the filler. GF were being incredibly protective and secretive. The anime staff had to rely on rumors they got second hand, like 'Ho-Oh is probably going to be part of the games plot?'
It goes even weirder when you have anime staff claiming that Celebii was always in the GS Ball, but they didn't even have a proper design for Celebii until further down the line. That means there was whole plot-thread that they had shove under the rug because of the games changing, and that's probably what GF was trying to avoid.
And what makes that even stranger still is that the GS wasn't in Gold or Silver, but they implemented it in Crystal and had it revolve around Celebii, which actually matches with what the anime staff claimed.
My best guess is that either the anime staff didn't originally plan for anything specific with the GS Ball, just that it would somehow tie in Johto to the Orange Islands. Then, that after hearing about Celebii (beta or otherwise) they decided Celebii would be the one in the ball. Then as GF refined Celebii, the anime staff decided to save them for the 4th movie instead. GF, without a specific story for Celebii in mind, GF took inspiration from the Anime and associated Celebii with the GS Ball in Crystal.
The GS Ball was last seen in the anime in April 2000 before it was abandoned, but it seemed they still had plans until the 4th movie's pre-production, because Kurt said to come back later for it and that it held some fantastic power inside it.
So, it was probably the anime staff that ruined Celebii for GF.