Alright, it died down a bit, so I will revive it.
About the goal gates: So we will have 3 of them, each in different levels of elevation, how about we give them some sort of soap bubble, so they can pop it with the air-bubble when it runs through it?
In a 3d and underwater environment, it would be difficult to measure distance efficiently, and thus could result in argues over goals
I had another idea, what if the air-bubble is the player is more than one?
Sort of like Quiddich, but the balls are all the same, it would create more chaos and be more interesting.
I will update the thread with the suggestions very soon, feel free to contribute!