Those are my knowledge from the scripts and the story board and the sheets at present.
Unfortunately, I don't exhibit the images at this point.
It's up to you after all whether you believe the stories or not.
1. Cosmo and tribe were traveling in space by the immigrant space ship to stop Metalex who destroy space.
Her sister said "This is one and only atonement we can."
In their immigrant ship, there was a big tree which they call their "Mother". Only the big tree has a memory of their homeplanet.
But one day, under heavy attack from Metalex, their ship was sunk with huge explosion, only Cosmo survived.
2. Another planets peoples have known the story of Chaos emeralds and Sonic as the legend of the seven gems with the incredible power inside of those.
3. Metalex took "Planet Egg" (I don't know what it is yet) of Earth. Sonic and his friends are trying to take it back from them.
4. Metalex has five officials(?) that is divided to the five colors.
Their names are;
Pale bay leaf, Black Narcissus, Yellow Zelkova, Dark Oak, and something red.
As for the rest, there are Metalex Vipers, and idiot troopers (in Japanese, it's ZAKO METALEKKUS).
5. In ep60, Shadow took a chaos emerald away and went to Eggmen.