Fluff :: What hits their soft spot? Does anything them into emotional goo?
I laughed. Noise doesn't... have... soft spots. He really doesn't. He's dead inside. This is confirmed canon.
Pistol :: Is this character skilled with a weapon? What’s their opinion of violence?
Outside of the Noise Blaster, Noise has never used a weapon in his life. (Hand lasers don't count 'cause they're a magic ability.) He isn't really fond of weapons, particularly melee weapons such as swords and knives. His opinion on violence is... well, that's what he does for a living, but he likes the buildup to it more than the actual fighting itself.
Question :: How often do they feel doubt? What topics are they defensive about?
Ho boy. This is one that's changed a lot for Noise in Citta, so pretty much everything from here on out has 0.02% to do with how Noise appears in the actual comic.
Doubt first came to Noise under the name Ibuki Mioda. She was the very first person in half a million years that had been nice to him without expecting anything in return, and that threw Noise for the biggest loop of his life. Then came Flammelle Evans, who was a super cool bro even after Noise basically told him "Yeah, I kill people for a living", and he only got cooler and bro-lier as time went on. For the longest time, Noise didn't want to call them friends, because he'd never had friends and he'd never needed friends outside of Mute, but of course any outside observer would say that yeah, they were his friends. If anyone ever tried to point this out to Noise, he would've gotten super defensive over it, since he didn't want to feel like he was replacing Mute and the concept of having more than one friend was a new one to him.