Well to start off, dog parks are not a good place for bully breeds, or dogs in general.
Here's a thread on that.
Dogs growl while playing, I wouldn't be worried about that. If he bites hard while playing yell, "OUCH". Pups should learn bite inhibition.
I'm not getting a good picture of the incident with the Siberian Husky, why was he growling?
He could have been trying to correct the pup, or some dogs just dislike puppies because they associate them with rude behavior.
I wouldn't call that aggression, generally a dog who is truly aggressive wouldn't have stopped attacking.