Breed? Do you own the mother? Generally, 8 weeks is the earliest(though, I think it should be 9-10 weeks) that puppies should be taken from the mother. If taken before, there's great possibility of social issues.
You need to not confine them to a cage by themselves, I would not be concerned with potty training anyway, just yet, as they're way too young to even be by themselves.
I would also suggest this when you're not around. It worked sooooo well for my dog when he was a puppy.