just looking at the picture there. I would be more inclined to go with female. Could you post better pics, especially of areas like the hackles and saddle feathers.
I am going with male, only because the she/he seems to be getting sickle feathers. She or he doesn't seem to be getting saddle feathers though. This my Americauna mix rooster who is 3 months old:
As you see he has sickle feathers and saddle feathers. He has a big dark red comb.
On the white one, 100% Rooster..lol. I'm assuming you already know that by now..lol. As far as your Ameraucana mix, if he hatched from a blue egg then he's actually an Easter Egger. If he passes the blue egg gene to his offspring and they lay blue eggs, they are Easter Eggers too.