Is he brindle? It's hard to see in the first picture, but it looks like his face is brindled.
First off, I would bet everything I own that he has zero wolf in him. Lots of dogs like howling, it's not just a wolf thing.
To me he looks a lot like a sighthound puppy. That thin curled tail, his face, ears, and even his body right now. Black masks are common in hounds, and so is brindle if he is brindle. He honestly doesn't look much like a lab or german shepherd puppy to me, all of those that I have seen as pups have a lot more bone in their legs and huge feet.