3. No, we will not make the entire system for you, nor post the EXACT trigger. It differs from map to map, and we're not going to make your map for you. However, might come along and post what they've done for their own map, or possibly post an example trigger. Anyways, if you want help, I would suggest that you try and do it yourself, and when you get stuck, post what triggers you have and where you're stuck.
I'm not sure exactly what you want for a duel system, but I'm guessing it would take the two 'top' players' hero and put them in a duel arena to fight. You can break this down to much smaller triggers, such as a kill counter which keeps track of which players are the top players.