here's what i found out when i was researching the exact same question - my ee's came from mcmurray and were even more confusing because they label them araucana/ameraucana and then in the description call them easter eggers, so i really didn't know what the difference was at all.
technically, ameraucanas have to meet specific breed standards. they have to have the right kind of comb, muffs and a beard (not one or the other or neither), retain the gray or green legs, and lay a blue-green egg. essentially, that would require them to be only one or two generations from the original araucana parent, because the muffs in particular are a recessive trait so many offspring don't have them or have incomplete ones. the farther away from the original cross you get, the less likely the desired traits will show up reliably.
ee's are crosses that somewhere in the ancestry was an araucana but there have been enough other breeds added in that many of the traits no longer show up - some don't have dark legs anymore, or have a different kind of comb - and depending on what crosses there were the eggs can be pinkish, even slightly red-violet, barely tinted, olive green, and of course blue or green. that is how they end up being called easter eggers, since there can be a variety of colors and not just blue-green.
