Oh for goodness sake, I'm so sorry you got such shoddy advice
Even if their mother was unable to feed them, the litter should have stayed with her until the ver minimum of 8 weeks. But you can't change that now. Please keep them together, crate and all. At 7 weeks, they still very much need each other for comfort and for learning very important lessons (bite inhibition for one) during this crucial learning stage in their lives. You can spend some one on one time with them, but please, don't separate them for long periods of time.
7 weeks is way too young to expect them to be walking nicely together on leash. Let them play safely in your yard and basement for at least until they are properly immunized. You may even want to consider puppy classes then, to get a better idea on how to reponsibly raise them and to continue in their socialization of other dogs and people.
There are several other members here who have pups from the same litter. It's not the end of the world and in your case, because of them being removed so young, it's a blessing.