Feed stores are notorious for not labeling breeds correctly.... and hatchery stock can be hit or miss on getting a breed with all the proper traits for the breed...
Wyandottes *should* have yellow legs, but blue and black also tend to have slate or black legs causing additional leg color differences... and yellow is recessive, if not bred to standard properly, it could get lost... hatcheries and feed stores are about quantity and not so much quality...
Wyandottes and Ameraucanas are completely different breeds... they *shouldn't* be the same breeds, but if the feed store messed up in labeling, anything is possible, lol...
But that would explain the smaller combs on your Wyandottes... Ameraucanas have pea combs, Wyandottes have rose combs... rose combs are much flatter and shorter than pea combs...