I've started watching Young Justice, and although I'm not familiar with Aquaman's* traditional powers from what I've heard they generally didn't involve shaping water but mostly restricted to telepathy/control over sea creatures and super strength (plus breathing underwater). Some of Aqualad's moves seem to involve shaping (but not creating) water. Some (the wave-like ones, the water shield, gathering water from different sources) but not all (making a hammer out of water) look similar to waterbending moves.
Have the creators said anything about this? Are there any hints that point towards or away from this theory?
* I think Aqualad was invented for the show but I might be wrong
edit: Doesn't Aqualad store a certain minimal amount of water with him (for the swords?) like Katara does in her water skin. Is this present with other heroes who manipulate water? Even if it isn't I admit it's minor and sort of obvious thing to create independently, but it still feels very similar.