sun is way too nice to harm a staffbot, moon has probably destroyed a couple of them before, roxy and monty wreck staffbots all the time (their sharp teeth and claws injure staffbots pretty badly)
I love how you're saying this as if there isn't several destroyed Staffbots in Sunny and Moon's room I believe. I know there's definitely more than one in Ruin, but I can't think if there's just one destroyed Staffbot with some severed Staffbot heads in Security Breach or more than one destroyed Staffbot. It's been a while.
I think Sunny could kill a Staffbot. Probably either indirectly, accidentally or in the most Looney Tunes way possible. He could do it though. We don't really know who destroyed the Staffbots in their room in Security Breach and if Sunny was trying to keep the lights off then maybe Moon wouldn't have had much chance to do it, ya know?
I don't think any of the animatronics have much remorse over destroying a Staffbot though. We know Roxy does it intentionally to keep the Raceway closed so I dunno, she might, but if she does it's only after the construction crew are killed. Ya know, like the trauma of that bullshit making her think about things she doesn't normally think of and that leading to feeling a little bad for the Staffbots maybe? Possibly?
They're all fucking haunted though. The animatronics don't know that, but they know there's something seriously wrong with them, but it's just kind of always been their normal so they don't worry too much about it. Empathy for the Staffbots probably starts and ends with a nagging sense that being destroyed is what the Staffbots want, even though they don't know where that feeling comes from. There is an unspoken rule not to mention it. Probably for fear of figuring something out they really don't want to figure out.
Actually, thinking about it now, Roxy and the Minis probably know what's up with them. After that first encounter with Mimic? Yeah I feel like they probably know. The Minis are able to put two and two together while Roxy, who doesn't believe in ghosts, can't see Tangle at all and has lived in the most haunted part of the building her whole so all this ghost shit is just an average day in the Raceway to her, I don't think she could figure it out. I think part of her would definitely feel it and would definitely understand something, but she would never think about it to a point where she would be consciously aware of anything.
There is just a feeling of familiarity with the Staffbots that's uncomfortably reminiscent of the silent dead. The pieces are there for her but, well...
She's not fucking touching that.
Anyway, Chica has destroyed the most Staffbots and we see her do it often enough that I'm surprised you didn't mention her in an ask about who destroys Staffbots. She's very good at it. The best even! No remorse from her! Fuck those guys! She has used their head like a football on several occasions and will do it again, just you wait! They make a pretty good bowl if you hollow them out too, she won't let them go to waste, don't you worry!
Freddy is the only one we don't have evidence for Staffbot destruction. In fact, he sucks at this so bad they just straight up murder him in (at least) one of the endings. Even if he has Monty's claws, which this series likes to pretend is what makes an animatronic strong and able to fight, he gets demolished. That bear can't fight for shit. Roxy, Monty, Chica and Moon could rip him apart like an orange can of beans. On their own. Probably blindfolded.
Sunny wouldn't do that though. As you say, he's too nice for that. He could be tempted though. If it was funny.
As for DJ, we've established in recent posts that DJ doesn't destroy the Staffbots. He plays with them like dolls and arranges them around the Fazcade and gets very annoyed at them when they start rolling away from where he put them so really it's a little like sheep herding to him. He would only damage a Staffbot if it was relevant to his current plot line of course.
Meanwhile, the Staffbots aren't worth the effort to the Minis. The Minis are like real life carnivores in this sense. They have survival instincts the other animatronics don't and part of those instincts is not wasting time and energy on something that has very little reward. Staffbots just aren't worth the risk. They could do it though, I'm sure.