I have several Naked Necks, and they are great layers and meat birds! Your looks to be pure NN, It doesn't look like he/she has the poof of feathers at the base of its neck, so if you hatch chicks from it they should all have NN!I think you might have some Wyanndottes, and maybe a few minorcas!?
First photo I see a Dominique, a bunch of either Leghorns, Partridge Rocks, or Welsummers, and a Silver Laced Wyandotte pullet as well as a few possible Dark Cornish.
Second photo is a Naked Neck with some Leghorn/Rock/Welsummers
Third photo is a pair of Silver Laced Wyandottes, boy on the right
Your next guessed breeds are indeed correct. The unidentified cockerel is again either a Welsummer, Partridge Rock, or Leghorn. Hard to say at that age. The next photo shows what appear to be Dark Cornish. Do they have sawtooth/single combs or pea combs?
The last two photos all seem to have "ordinary" saw toothed combs. I had thought they might be partridge rocks, but they don't seem to have the barring like some of the others have.
Sorry about the dirty nest boxes where the pics were taken...they are in my storeroom until I need them again. It's the only place I could find that the little critters would stand still long enough to get pictures taken.