Now that does change things. At six weeks, there should be little to no red on those combs. Also I would expect them to not have wattles yet either. I think your gold laced wyandotte is a roo with those bright red wattles. I think the black one is a pullet for sure, but I'm on the fence with...
I think you are right on the breeds. The White/black ones are silver laced wyandottes, and the gold/black ones are gold laced wyandottes. They look like pullets to me - how old are they?