CEO of aroace buzzkill

Nezha was a fairly easy character to answer these questions with. From his characterization in the film, we know that he wants to be a hero! Someone who fights on the side of the good, and protects those who deserve protecting (while punishing those who deserve punishing).

If we bring in the element of him being excited for his promised glorious fate from Investiture of the Gods, and read further into his struggle with Li Jing over whether or not his violent justice is itself justified, we can infer that Nezha does not want to be viewed as a naïve, careless child. He's eager to prove that he's already capable of making a difference, despite his age.

What makes it interesting is that Nezha is, in fact, somewhat naïve and careless. It's not really his fault---what else would you expect from a sheltered, naturally gifted seven-year-old? Then again, he's a lot more mature in some ways than his age would suggest (e.g. his confidence, sense of justice, and determination), so maybe he's not too far from realizing his flaws and growing through them.

Going by this interpretation, we have several sources of conflict: between him and forces of evil, of course, but also the question of whether or not what he's doing is actually righteous. Also, a conflict between him and others who see themselves as wiser or more just than him (parents, enemies, etc.) simply because of his age and position.

Ao Bing, on the other hand, is pretty one-note in the source material, requiring more between-the-lines reading.

First, we know that he's on fair terms with Ao Guang, with the way he offers to confront Nezha and how Ao Guang trusts him to carry it out. He's prideful and smug, labelling Nezha as inconsequential and too big for his britches (y'know, if Nezha actually wore them), and somewhat mischievous with the way he gloats to Nezha about having eaten Xiaomei.

But Ao Bing is the Third Prince, which, if you're being all critical about a film that's not really intended to be that deep, makes you wonder where the First and Second Princes are. Shouldn't they be more important to Ao Guang to lose and demand revenge for?

Another meta-narrative detail I found interesting comes from this article (thank you ryin-silverfish for first sharing it) that discusses where the artistic direction of the film could've been improved, one example being of Ao Bing's comically large arm swings as he first appears.

"本身这个动作就与这个情境显得有些冲突，更何况这个动作原本是身材肥壮的花脸角色专属的，敖丙这么一个瘦若干柴的家伙做出来很是别扭。当然，也许画这段戏的动画设计师本意就是要营造这种滑稽的效果。"

Machine-translated: "The action itself clashes with the context, especially since it's a move typically associated with stout, huāliǎn [painted-face] characters. It looks awkward on Ao Bing, a rather thin and frail [literally, as thin as dry firewood] character. Of course, perhaps the animator intended this comical effect."

Twink Ao Bing confirmed... /j

We could interpret this from a Watsonian perspective as well. Maybe Ao Bing is trying to embody someone bigger and more important than he actually is. With how easily he gets killed off, he's certainly not that important to the audience. And with how easily the Dragon Kings jump to carefree festivities after Nezha's death, maybe he's not that important to them, either! Can you imagine? Being so forgettable to your own family? At least Nezha never has to deal with that particular issue. ...Where was I?

Therefore we may answer the two establishing questions like this:

Ao Bing wants, more than anything, to prove his worth to his father, that he's more than just the backup prince who is only made important through the absence of his two older brothers.

Ao Bing would hate to be viewed as useless and generally irrelevant.

Taking it this way, Nezha and Ao Bing's motivations are actually quite similar. They both desire to be someone important and of value. Except, Nezha can already see, and excitedly anticipates, how he will become that person---as a general, a warrior, a hero. To him, his relationship with his father is an obstacle in the way of his destiny, something better off left behind.

Ao Bing's future is more uncertain, so he devotes himself to the path he can see: being the son and prince that his father wants him to be, or what he thinks his father wants him to be. With his identity and goals being so wrapped up with Ao Guang, and the idea of filial piety more entrenched in his mind, it is of course harder for him to ever strike his own path.

Now, put these two together in the same room and see what happens! Do they overcome their differences, or do they end in bitter separation? Only time will tell.