Without knowing more about the parent stock, it's really hard to say what the babies could be. Olive egger is simply a term for a bird that has one dark brown egg parent and one blue egg parent. There are several different crosses that can be used to make olive eggers, so you really can't count...
Barred Rocks lay a regular light brown egg. Welsummers usually lay a darker egg, not a chocolate like the Marans, but more of a reddish terra-cotta color. They're often speckled, too. Here's a pic of my hatchery Welsummer's eggs
Your black and white birds look to have rose combs? That would make them Dominiques, and they're both female.
Your other birds look to be probably Welsummers. Slight possibility of them being brown Leghorns, you'll have to look for white earlobes as they mature. But they look heavy enough to...