I will agree that the size of the pups compared to the parents is not really an indicator of anything other than they were healthy pups.
I have a yorkie poodle mix that was bred by friends and I seen him 2 days after he was born. He came from a pure toy poodle.. 4 pounds and a yorkie poodle mix also 4 pounds..they did look more like yorkie pups than yours do but they were also big pups. Tucker was a full pound at 2 weeks old. He is know a solid 9 pounds. He to me is still small, but when you put him next to his parents he looks like the jolly green giant..lol.. your new pups will be bigger but I think they will stay under 10/12 pounds.
I dont think that your pups are full bred.. at least not all of them. The one does look just like a little lab but I highly doubt a lab is the father..
The only way to tell who or what breed fathered the pups is by dna testing, but if you arent selling them, then why bother..
They are cute pups and will be easy to give away. I highly suggest that you get the parents fixed so you dont have anymore "oops, who's the daddy" litters and not to mention its healthier for both animals..
Good luck and congrats with your pups..