Just a correction: An Easter Egger is a bird that carries the blue egg gene but does not conform to any breed standard. They could have Ameraucana in their lineage, they could have Araucana in their lineage, they could have Legbar in them, they could be purebred Ameraucana that don't meet the standard. It doesn't matter what they look like, it doesn't matter what color their legs are (LOTS of EEs don't have willow legs) all that matters is that they lay a blue or green egg or carry that gene (if they're a roo).
Since the blue egg gene is closely located to pea combs and puffy cheeks on the chromosome, most EEs have those. Since slate legs (required for an Ameraucana) crossed with yellow legs gives willow legs, lots of EEs have them. But it doesn't matter what the bird looks like; if she lays a blue or green egg, she's an EE. If she does not, she's something else (including a regular mutt instead of a mutt with a fancy name).