I too agree with the GLs being girls, and I think that the two Silkie crosses may be as well. I don't see any streamers in the head or definite signs of maleness. At that age, you should. They all look close to laying age, so you will know soon.
At 16 weeks old the wyandotte crosses would have far more comb/wattle development if they were cockerels. They are all pullets. The silkie mix looks like it probably is a cockerel.