Yes, he looks very much like the Elkhound part, but maybe Elkhound/Lab - something to account for the floppy ears and slightly golden, shorter coat. Are his paws webbed?
As Elkhounds are friendly but independent in nature, that's the stubbornness you describe. Keep working with him, be consistent but firm, and he will eventually learn that you are in charge - he's still a teenager now, after all, and will be a great dog. I am glad you are using the halti - that will help. Any classes you could take with him will help focus him, and especially as you are home #3, that might be a good thing to do, to help cement the relationship between the two of you.
Will he play fetch? Some tosses of a ball before the walk might tire him out some, and make walks easier!
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