Birdnut is 100% correct. EE's are actually not a 'breed', but a dilution of the Ameraucana/Araucana breeds. So hatcheries can go nuts and do whatever they want, and still call it an EE (though they love to lie and just call them Ameraucanas too).
The ideal look to an EE is a muff, pea comb, green leggs, and lays blue/green eggs. However, you can mix, match, substitute, and slurry any of these features with other chicken breeds, and still call it an EE.
For example: You can have a straight combed, no muffed, green legged bird that lays brown eggs. The hatchery would still call it an EE. You could also have a pea combed, yellow legged, muffed bird who lays brown eggs. Still an EE. The combos go on and on. Essentially they will call it an EE all the way up to the point where it doesn't have ANY of the desirable EE features.