Allllright, we doing this. Roll me a stealth first to see if you can get a sneak attack, followed by an initiative. That being said, the biggest goblin is also the furthest away from you at about 50 feet. Unless you plan to hurl your new harpoon at him, you can’t reach him in one move action and attack. You’re harpoon btw is basically a javelin but with a higher Damage die, so I’m pretty sure your martial arts stuff still applies to it.