Whenever you get Ameraucanas from a big hatchery, they will never be true Ameraucanas (I believe the exception is Meyer's As they do say theirs are not to be confused with EE and others have great reviews on them but don't quote me on that). They will always be EE's (I love EE but it's false advertising and it's wrong) EE's can be Ameraucanas that don't fit the Standard or mutts. Anytime you see ANYONE saying they have Ameraucanas or Araucana's and that they "lay a range of colors" or "lay blue and green eggs" then they're just EE's. True Ameraucanas will not lay anything other than blue, and is never spelled with an i. I always tell people who get the Ameraucanas/Americanas/etc from feed stores that they're just mixes and the likelihood of blue eggs are slim. You could get blue, no doubt.... but you're much more likely to get browns/creams/and greens. I've only ever had Townline Ameraucanas and between me and my cousins who all got ours from that hatchery, most were green a few were brown. We've never gotten blue in all these years. Ever. I do know a few people who have blues from there, but they're few and far between. My most recent Townline chicks laid bright green eggs and one that laid a sage color.
Never expect the best from hatchery birds. I think you guys will still love your birds and I'm sure you'll get a variety of color from pink, brown, and green. I just wouldn't get your hopes up for blue as it's hard to come by.
As for the feed stores not knowing the difference... the workers aren't there to learn about every breed detail. Heck I'm surprised when they tell people the correct things the chicks need. A guy came in with a box of dead ducklings because he had been told to feed them grit and grit alone. I corrected him and the store reimbursed him for the ducklings with new ones and the proper food for free. I see the breeds mislabeled all the time and correct them. I put one guy in his place because he kept telling people the pekin ducks would fly south for the winter. They just see the labels on the boxes when they are shipped and dump them in a tub. Rarely do they have proper knowledge on the chicks.
I will say this, Easter Eggers will always lay better than an Ameraucana. I get massive green eggs from them about 6 times a week whereas when I had breeder quality Ameraucanas their eggs were decent size and stunningly blue, but I might only get 3 a week. Hatcheries are about egg production - not color, not appearance, and not shape. If you want birds that lay blue eggs, it's best to seek out hobby breeders or serious breeders who have proof of their blue eggs so you know what you're getting.