So they would be about 16 weeks in the photo? I agree, they look like pretty Golden Girls! Here is my Buffy around 16 weeks....She was the first of my girls to start laying eggs (at 20 weeks). Her comb and wattles had just started to redden and grow.
3 definite pullets. I'm not positive on the last one... Can you get a full side view?
I know BOs are known for having large combs, so at 16 weeks the last one could very well be a pullet. But the hackle feathers look a bit like a cockerel's.