Faverolles are easy, they have different coloring. In the Salmon faverolles, which are the most common, the girls will be a salmon color on belly and chest and a darker version of the same color on their backs and tails. Pullets are also a bit squat. Very short legs and they tend to waddle. Roosters will have black wings with more everywhere else. Roos should also be getting their pointy saddle feathers by then.
by comb alone i would say the multicolored ones would be your girls and the two more solid ones would be your boys - which does not jive AT ALL with what feathersite would indicate the chicks coloring should be (according to what I read on feathersite the salmons will have brown wing tips when a girl and black wingtips when a boy - making them easy to sex -- yours has white/creme wingtips!! -- in blue faverolles the girls will be solid blue and the boy multi ) But I have never had faverolles myself - so have no practical experience to share. I did do a search on google images for "6 wk faverolles" and the coloring was clear enough on the few pics I saw that you could clearly tell who was the girl and who was the boy ... here is one link : https://www.backyardchickens.com/t/198463/salmon-faverolles-for-sale-in-mass-price-reduced
Where did you get them from?
hope this helps...