Yours are too small to separate yet - I wouldn't separate before any of the pups has reached 200-240g in weight; at the moment, they are by no means ready to leave mummy yet!
As your pups are very small and between two to three weeks behind in development compared to others who were born large and whose mother wasn't ill herself, I would rather go for weight than age as an indicator for separation.
No, not at that small size - they are the size of normal newborns to max. one week old! To be able to make babies they need to be better developed physically.
Some babies do rumble long before they can get going, but he will still be too small to be able to get mummy pregnant when she comes into season at 15-17 days old, and then you have another gap of the same time before she comes into season again.