Your hen is a game bird. Scrappy little things, they're known for being great foragers and mothers. Usually not the friendliest bird in your coop, but won't get picked on by larger birds, either, unless she's broody.
Your barred rooster is probably a black sex link, meaning his momma was a barred rock and his daddy was non-barred. He may be hatchery quality pure barred rock, but they're usually a lot lighter. He's pretty dark overall and his barring is pretty messy, not nice and crisp, making me think he's a mix.
Your yellow chicks aren't buff orps, they're feathering in more like some red --production/new hampshire/etc. Could also be red sex links. And I can't see your dark bird, but the puffy cheeks tells me it may be an easter egger. Post more pics of the babies in 4 weeks or so, we'll be able to give you better info then.
