I just joined today and saw this very interesting thread!
I thought I would throw some information in, and clear up some mis-information.
Newfoundland Puppies definately, absolutely should be fed a puppy food, but it HAS to be Large Breed Puppy food. The dam should have been fed this as soon as she was bred and during her recovery time unless she is normally fed a raw diet.
Newfoundland dogs should be living well over the past acceptable 10 years old. Mine are averaging 14 years old. They mature (growth plates are closed and they are sexually mature) at 18 months old. The males should not be neutered until this time to reach full growth, not just size, but bone density and full skeletal muscles. Females can and should be spayed at 6 to 8 months old.
I spin my own Newf and Alpaca wool (that's where Laurie the Leonberger lady got the idea from!), so grooming isn't so much a chore as it is a welcome harvest. I knit dog sweaters for the local dog shelter and OSPCA with the Newf wool. It's so warm and "green".