I'm not much help on the puppy issues because I've mostly only had rescues or rehomed ones that were a bit older. That being said, they do sleep a lot..most of them anyway. Maybe the growling is his way of playing, just depends on the growl. Is he growling during play or when excited? If so...
Thank you for all your rescues efforts, that's amazing. Can't add too much as Lynns given great advice as usual. What city and state are you located? Perhaps someone knows a good behaviorist in your area.
Hmmm, is it possible he could have gotten bitten by something? Not to change the subject he looks like a handsome little dude
Here are Lady's cherry eyes.