They're leghorn mixes. They all clearly have leghorn as the main part of mix but with what, is anybody's guess. The blue legged hen indicates the cross that led to her was with something white skinned with blue legs.
Bigger yellow legs is definitely a cockerel. He's still young but hes already showing the roo tail feathers and not sure if that's a stain on his wings or that's the roo feathers coming in reddish. If it's color, he probably will get some more on the wings, perhaps some on the saddle later. He will start trying to crow in a few weeks.
the chick with few black feathers is typical of white leghorn bred with a colored bird, a common example are California White- cross of white leghorn with California gray.
If you can have a roo and want to hatch, this group should be a very good one for producing great layers.