Some patterns do that. Sometimes you need to put a sheet of paper under a few feathers, or otherwise isolate them to get a good idea of the shape.
I'm not sure either way about your darker chicken, but I certainly have seen pullets and hens with pointy markings inside rounded feathers.
Some cockerels get their narrow pointy feathers at a younger age than others. So male feathers would mean male, but rounded feathers at this age could mean female, or could mean a male who just hasn't grown those feathers yet.
For the one in the front of the photo, I notice some of the feathers in the saddle area almost look like slender lines: black line in the middle, white line on each side. I am fairly sure those are male-specific pointed feathers that are trying to have a pointy marking (the black line) inside a narrow feather (the white lines on either side being the outer part of the feather.)