re: What type of dog is this? Purebred lab or mix?

Except for less white flashing, your dog looks almost exactly like my Layla, a Lab/Retreiver mix, when we first found her as a pup wandering the highway. It's kind of hard to tell for certain when they're that young. She is very fast, very smart and high energy. Keep the dog. You won't be sorry, it will love you unconditionally to its last breath. Here's mine, now about six or seven.

Not the high energy pose.