11 weeks old, I'm thinking lighter one maybe a pullet? Darker a roo? I'm horrible with these silkies! The lighter one has a straight comb, but no growth on it.
Posture-wise they both look like pullets to me. PS: I do now see the black one seemed to have a bigger beak and the leg feathers have more of a puff to it than the gray one. So I am leaning more roo to the black one.
I believe you have hit the nail on the head with one pullet and one cockerel.
The single combed one is definitely female, but the darker one definitely appears to be male.
Alright that's 2 girl votes for Iris. Hera is probably a Hercules lol I may hold on to him. For another month, in Hope's that comb dont grow! I've had like, 10 or more silkies. Majority boys.