The red feathers on the NN's wings scream roo to me... but where's his tail? I would've thought that they'd all have saddle feathers by now, but none look evident. Everyone's stances look rooish to me with the exception of the white one, and everyone's comb looks so big and red. The comb and wattles of my JG hen took forever to redden up and did so just before she laid her first egg at ~6 months.
By looking just at those pics, I'm going to say that I'm 90% sure that the NN is a male, 80% that the black JG is a roo, 70% on the blue JG, and 50-60% sure that the white one (EE cross?) is also a roo. Pretty birds, though!