I bought eggs off eBay where the seller had a similar set up to what you described and my babies look very similar to yours. Do you have updated pics?
This chick hatched out of a blue egg and has a pea comb, so I'm guessing Cream Legbar rooster over Blue Americana (and I'm already almost certain it is a boy).
This chick hatched out of a brown egg (but not dark like a Marans) and has a straight comb. So cream legbar over.... But looks soooooo much like yours.