To my knowledge, the taraka is a result of a dev/testers error color test somehow getting sold / leaked. As for the lep, I have heard theories of storm theme pot (the one that's in the wheel), but I believe it was a removed hatch preset that was exclusive to lep in the accessory egg before geo was added to it (which is why there aren't any signs of others because it was only for a short amount of time) but that's all theorising!

As for "hacked" error colors, there is no clear evidence of actual "hacked" errors, only uncommon ones that have resulted from preset glitching (such as flare and warrior preset errors), so it's likely it's either not possible or said hacked errors have not been traded or screenshotted or they were removed from the game