ee ONLY means red-based. "Chestnut" and "sorrel" are the color the horse is. An eeCrcr horse is not "chestnut with cream", it is "red-based with cream" and it is palomino.
Horses are red-based or black-based in their color. Beyond that they are a color dictated by any other modifications, if any, made to the base.
As for gray - I too hope gray has been tested for. This simply does not look like JUST a red-based champagne.