Probably not.So you think the black and white barred one is a male? (The last pic).
I think the black and white one is your Cuckoo Maran, and I'm not seeing any signs of it being male at present.
Blue Sexlinks would have males that are actually blue, because the breeders manipulate the blue gene carefully-- crossing a splash parent to a black parent produces chicks that all have blue. Common for that kind of sexlink, not common with any other kind of chicken that is supposed to have blue.