What Breed Is My Puppy?

I have a gorgeous, amazingly, clever little girl called Lily. We were led to believe she was a Lab, a very small runt rejected by the mum. She was hand reared. She was very small when she came, but the vets assured us she was the right age. Now 5 weeks down the line she's changing. Lots of people have had opinions that she's mixed, but not sure what with. She's definitely a people dog. She shows no sign of aggression at puppy class and excels in training. I would love to know her breed. She came with no papers. Mum and dad were only seen via emails with Lily present at the time. I can provide pictures of mum and dad if this helps, but I will post pics of our girl for now. She is currently 12 weeks old and weighs only 6 lbs. She eats perfectly well and is in great health. Any help would be appreciated. Thanks.