I voted for Vince but not without a lot of thought.
Was Queenie just annoying or was she really in Mark's face - crapping in his yard and then taunting him from the window (Now go away, or I shall taunt you a second time)?
Landru ran Art over the fence, which was pretty good for a mangy mutt.
But Vince shared his food with Queenie, he found the femur, he had a field day and he barked at the gun totin', crow poppin' Art. What more can you ask of a dog?