I have three Blue Orphingtons. The big one is 12 1/2 weeks old and the other two are 11 weeks old. I have never had chickens this young and I would like to know if they are pullets.
It's hard to tell, did you get them from a breeder? If so, do you have pictures, or can you get, pictures of the parents combs/ how big they are. To me, it looks like for being 3/almost 3 months old, they don't look a lot like cockerals, but we only had a few Orpingtons, and only pullets, so I could be wrong, but they look like ours at that age.
I don't remember what they looked like exactly but i'm pretty sure they had a dark red face and big combs. It was a while ago. I just hope they are pullets. I was told they were pullets when we got them. I really hope they aren't roosters.
Generally Orpington's have larger combs, so that is why I think all of yours are pullets, it seems to me they would had developed more of a comb if they were cockerals by now. But, I could be wrong, but I think you're pretty safe, they all look like pullets to me.
I have Buff Orphintons. You top one looks like a cockerel and the bottom one looks like a pullet. They are very fluffy birds, so I could be wrong, but the tail feathers on the top one seem a bit long to be a hen.