If her dogs are well behaved and well socialized then there isn't a problem. When you hear in the news that a pit bull just snapped and attacked somebody but never showed any signs of aggression that is a myth. Most often it's the owner trying to cover for the dog that they allowed to go untrained because they thought the dog would listen when they said "no". A properly trained and socialized pit bull will display absolutely no human aggression for any reason other than clear, obvious self defense, and even then it's pretty iffy. Fighting dogs had to be safe to handle, especially back when bull baiting and dog fighting were legal and one's fighting dogs were often also a family pet.
The lab was probably the runt of the litter, perhaps bred from two dogs at the lower end of the breed size.
Your friend doesn't need more room, but she does need to actually take those dogs out for walks. Bored dogs in general can be a nuisance and a dog that is constantly overly bored can become agitated and reactive, which may lead to nippy-type behavior and a general lack of patience for their child. Your friend owns two breeds that require a pretty decent amount of exercise every single day, particularly the pit bull. They are high energy dogs and that puppy, when older, should be getting an hour walk every single day.