Definately not a French black copper maran or it would have lightly feathered legs and feet.
From the pics I see no feathers at all on the legs and feet and they should be feathered from hatch.
They look just like my barred rocks, one of mine has a dark overlay on her legs also. My BCM's have feathered legs, and no barring whatsoever. While I haven't seen any cuckoo maran chicks, I think the little white spot on their heads is kind of a barred rock trademark. Maybe you can find someone on here who would post a picture of their cuckoo maran chicks so you have something to compare them to.
Otherwise you could find someone who breeds a variety of Marans and ask them for input.
Barred Rocks have strong barring - the white is super white and and the barring is clean - in my humble experience the barring on Cuckoo Marans is more like what you see on your chicks - the white is not as strong and the barring is kind of - messy. I just have hatchery stock so I know that plays a part in mine - but even in the pics on feathersite.com that much holds true
My hatchery stock cuckoo marans don't lay as dark an egg as my blue marans hen from a breeder - but they do lay a terra cotta egg darker then your avg "brown". I guess you just have to wait and see - you can always ask to see their eggs next time. I am kind of in the same boat as you tho cuz I bought a couple bcm from someone advertising on craig's list - did say I would love to see the eggs they came from but they just said "they're dark" - and now I am waitin for them to evolve and see what they lay
I just picked up my chicks on Monday (2BR's,1Bcopper maran and a few other types) I'm reading this thread and running up and down the steps to look...lol Now I know i only purchased 2 barred rocks and they both look like the chicks in your pics with the white spots on their heads, and the one that doesn't have the spot i'm guessing has to be the Maran. A few threads say check the color of their feet/legs and unless i'm going color blind, they all look pink to me..lol Guess me and you both will be looking to see what comes out of them..lol
Did you ever find out what the chipmunky ones with the "V" on there heads were? Are they EEs or Welsummers? I got one out of the EE bin at TSC that looks exactly like them, but looks NOTHING like the other EEs.