Shredding. Be careful not confuse mites and a neck molt. I have found with mites comes a fairly quick, tell-tale drop in feather quality.
Don't confuse Ameraucanas and Easter Eggers. Easter Eggers are mongrels that happen to lay blue eggs. They're no more stable than a mongrel that lays white eggs. An Ameraucana is a a breed. I would not compare a white egg laying mongrel to an Ancona or Minorca just because of egg color. The same is true for Ameraucanas.
Any breed, again, any breed can go mean. Temperament is a matter of selection, like most things. Ameraucanas are want to have a respectable amount of energy, like all birds bred first for egg production, but poor temperament is poor breeding.
WAY TO OFTEN on forums such as these are traits that depend on the individual breeding program attributed to entire breeds as if they were such. It is very important to learn about the hereditary nature of traits and then recognize that it is in the breeding that one enhances or eliminate the traits. When one chooses a breed, one is choosing to breed it. The truth of your strain will come in the fact of your selection or absence thereof.
In no way can one get a handful of birds and then make statements about a breed. Indeed, the only traits that are breed based are the standard-based traits. Everything else is arbitrary unto the selection of the particular strain. Breeds might be supposed to be or intended to be such and such, but they only are this or that trait if the immediate selection criteria around the given individual bird are in place.