Yeah, I got that. Still, the others don't exactly stop him....
They do. Read it my posts carefully. And even if they did, Neo doesn't care. What, you expect him to just stop after being told to stop?
No. It seems as if Neo's raison 'd etre is to be a jerk, and he'll stop at nothing to be one.
Well, yeah, sure. But, I would expect Neo to cause him problems with his general assholishness.
Again, he does. You know what happened to the three of them after Neo badmouthed Sakura, right? And even if Rattus said to Neo to tone it down, Neo's like "No, should do that." or something.
Honestly, Yukina I know very little of. She doesn't seem to do a lot.
She's just silent because that's her personality profile: the stereotypical Yamato Nadaeshiko and moe girl stereotype. Otherwise, she's the engineer and blacksmith of the group.