Wait, probably should ask this. I'm considering Celebi for Link - it's a Legendary Pokemon, but it's basically unknown if there's more than one - Bulbapedia says,

"Although multiple Celebi have been seen at one time, it is unknown if they are different individuals or the same Celebi from different time periods. Therefore, it is virtually impossible to determine exactly how many Celebi exist."

At the very least, the Celebi in G/S/C and HG/SS doesn't seem to be the same one as in the PMD games, so would that be okay?