You should be able to tell now by the comb, but pea combs, especially on BBS birds, can be quite tricky. I always look for the iridescence on blacks, the hawk-face on the boys, and the size/redness on the combs.
Ha! These always declare themselves late. We have a black Ameraucana rooster who escaped the Amish Butcher by cackling like a hen. The man picked the cockerel up, said 'This is a pullet!' and sent him back!
The black females will have the green sheen too. The last one looks like a rooster. The rest I see look like girls. The only one I'd watch is in the first pic on the right. The comb is wide, but not raised yet. Reminds me of my girl that kept me guessing for a while.