Wait another 5 weeks, you never know. Some of them could just be fast developing pullets. You can never be 100% accurate by looking at the comb and wattles. Time will tell :thumbsup
Usually they mature within 16-24 weeks of age although your Brahma willl take up to 2 years to fully mature, if you have a Brahma hen it should begin laying within 25-28 weeks of age. If you have a rooster it should begin crowing within 4,5,6 months of age.
:he:old
Them ‘rooster tail feathers’ also known as saddle feathers don’t develop until the chicken is at least five months of age. And this is a Brahma that we are talking about, which should take even longer
:he:gig
Bearded ameraucanas should still have wattles, you’ll just find it hard to see them.
The brahma looks like a roo, you say they’re all 5 weeks old. Yikes is right. But you never know until their fully grown. I could be wrong