where did you get your chicks from?
Of the chicks you have listed:
The legbar should have a tiny single comb which will look like the teeth of a hair comb, with yellow legs.
The marans should also have a tiny single comb with whitish legs. It may or may not have down on the legs, depending on if its of French or UK standard background.
The Wyandotte will have yellow legs with a flat, almost non-existent comb.
The ameraucana will have slate legs with pink feet or foot bottoms and another flat almost non-existent comb. Additionally, it will look like it has puffy chipmunk cheeks. If your ameraucana has green legs, or any yellow to them at all, then its an easter egger and not an ameraucana. Additionally, if no puffy cheeks, then its also an ee.
ETA, post pics and we should be able to help you tell the difference.