The other question is in relationship to what your were describing should be evident on a dominique that wasnt present. I ask because there is a black in the bunch that has white on his wings but everything else is pretty similar ( not sure about comb type i cant really tell until older )
Dominiques have white barring across the feathers, all over their body. This should be visible even in the amount of wing feathers they already have.
It is fairly common for black chicks to grow a few white feathers in their wings. Later, those feathers are usually replaced with black ones, so the chicken is entirely black at maturity. But such feathers would be entirely white, or have large patches of white, so they look different than the lines caused by the barring gene. Barred birds can also have white feathers in their wings.
The barring gene makes white lines across the feathers, no matter what other color the feathers are. So a "barred" or "cuckoo" chicken has those white lines on black feathers. "Cuckoo" just means they are not as tidy (various other genes affect this.) But the white lines can also appear on other base colors. Some of those have names (example: "crele" is white barring on a Black Breasted Red base color. Examples include Bielefelders, and Crele Old English Game Bantams.) Barring on some colors does not have a special name (example: Rhodebars have white barring on a chicken that would otherwise look like a Rhode Island Red, but I don't know of any special name for that color.)