It's hard to tell because it's not a great angle, but I think the single combed bird is a girl. I have a single combed SLW that I was worried was a boy for a long time, but am finally sure that she is in fact a pullet. Yours looks exactly like mine did in the face at 3 months. I don't really want to venture a guess at the others, since they all look like they are the same gender to me, but I really don't think that the comb/wattles on that last bird are large enough or red enough to be a boy at 3 months based on my own experience with a single combed wyandotte.