1 and 3 have darker colored bodies, so if they are the pullets I'm guessing 4 is another pullet since its body is also darker, and then 5 and 6 would be cockerels. That's one way to read these chicks but I am not sure that it's accurate.
Unless you get lucky and a breeder shows up to help out...
These look so different from other chicks I've seen of this variety. Much lighter and more brown. Are those white patches on the back of their necks part of the head spots? It's so hard to tell. I think your guesses so far are correct, but the other three may just take more time to tell...