The chick does have some comb and wattle development, but I'm leaning pullet because of how even the blue coloring is on this bird.
Around 12 weeks, it will get red shoulder feathers if it is male. So it may take a while longer to be sure.
It depends on where the eggs came from. If from a hatchery, then maybe a mistake was made.
If from a backyard breeder, then the black one is probably a mix of some kind.
In the second photo, the chick on the right is male.
They were breeding Easter eggers and still are. The hatcheries didn't use the term Ameraucana until after that breed became standardized, and they played no part in that.
Only birds sold by color variety by the hatcheries are likely to be purebred Ameraucanas. Price differences usually tell...
The orange bird in the background in the first picture is a cockerel, in case you didn't know. The other cockerel is in the fourth photo and has already been pointed out.
The black pullets are all probably Whiting True Blues.
The white one with single comb and no beard looks to be a Whiting...
Roosters sometimes alert hens to danger and a few might attack a predator, but mostly they are not effective for flock protection. The dominant hen tends to take over those responsibilities anyway when there is no rooster around.
The dark faces of this variety cover red, so it is more difficult to tell the gender. You're looking at comb size alone.
They do look small for 12 weeks old. Age is important when judging comb size. But for now, I think they all look to be pullets.
Purebred blue Plymouth rocks are very rare, but the name blue rock is often used for the hybrid also known as Sapphire Gems. That's my bet just because the cockerel doesn't seem large enough to be part Jersey Giant.
But I agree with the above post. There is no way to be certain.
She's a Dixie Rainbow, now often called simply 'Rainbows'. It's a fast growing hatchery hybrid raised to be good for meat or as an egg producer.
The breeds used to make them are unknown but I would guess meat strains of Delawares and possibly red rangers are used. These won't lay blue or green...