The two black Cochins look like definite pullets. The white Cochin looks more like a cockerel than pullet to me.
An Update: Both Black cochins appear to look the exact same and I feel they are pullets. My youngest one's are 16 weeks, and I only have one that is crowing with a big comb. All of my whites have no combs and are not crowing, some have more color but they are screaming pullet. I got very lucky and out of 7 Cochins straight run, I only found one rooster.