Yes, they'll be mutts. No doubt gorgeous mutts. Are they real rumpless Araucanas and purebred Ameraucanas?
Easier question: did you buy them from a hatchery?
If so, you have Easter Eggers. If not, you might have the real thing and you should breed them separately.
And sorry if we are all bristling up, people get very annoyed when "Araucana" and "Ameraucana" are misspelled.