My boy was like Jaws on speed when we got him, and we were tearing our hair out thinking he would never stop being a biter so I know how you are feeling at the moment. But pleased be assured it is perfectly normal behaviour, and the growling sounds like he is excited and talking to you, something our boy also did. Logan is 18 months old now, and the softest dog you could wish to meet, so I promise you it does get better.
When we got our girl, the biting was the thing we were dreading most, but she hasn't been a biter at all, so every pup is different.
Good luck, you do get to a point where you can start enjoying your pup honestly
