No idea about the white one, but the barred rocks... the one in the front with his head pointing to the left... he's a rooster. Based on coloring, the other 2 are likely hens, but if you can post shots of their comb growth, that would help. But the front one is much lighter and has a largish red comb which typically means you have a little roo on your hands.
Ducklings...
the 2 you got at TSC - the all brown one is likely a khaki campbell and the black with yellow chest sounds like a black sweedish.
The other 3 - one sort of looks like a blue swedish, but if somebody with a mixed flock gave them to you, they are likely mixed ducks.
Since you have differences in age/size, you can try to keep them all together, but have plans if you need to separate them for a bit. A mixed flock can normally exist peacefully, but sometimes there can be issues - same with brooding mixed sizes/flock - can work well or it might not.