When we first met Dani back in Marvel Graphic Novel #4, she had... anger issues. She lived in isolation because she couldn't control her powers, she was emotionally volatile, mistrustful, and prone to outbursts. When Pearce's goons killed her grandfather, she only agreed to help Xavier so she could plunge her knife into Donald's back and get revenge. But by the end of the graphic novel, she was more concerned with her new friend [Rahne] getting injured, and opted to take care of her during the final battle in lieu of going after Pearce. And then she opted to stay at Xavier's school to learn to control her powers, which was her grandfather's wish, instead of worrying about avenging him. So it showed some personal growth.
Throughout her run in Volume 1 and subsequent volumes, Dani remained headstrong and unafraid to challenge authority. If there was something that she perceived as being unethical or wrong, she would confront it directly. She also became first the de facto team leader, and later on the actual, designated team leader. So no surprise -- she was the one willing to take the lead and make a principled stand when she saw something she didn't like. She continues to do that today [see: Bishop's War College #1]. So it is unlikely that she would go along with Cable's more violent tactics and blindly follow his lead -- just not her character to be a "good soldier."
I personally don't think that Dani has an anti-killing rule. She may prefer non-lethal, but I think she wouldn't hesitate to put a threat down if she had to. I don't think that she's driven by rage anymore, like she was when we first encountered her as a volatile teenaged rebel back in MGN #4 -- if anything, she's pretty level headed now -- which is what you'd expect from a leader.
But she wouldn't hesitate to put her foot up someone's @$$ when she deems it necessary, which is why I have difficulty seeing her fit onto that iteration of Cable's team, with those teammates, and their lack of qualms about violence. Especially back then. She stood up to Professor X early on, and Magneto when she disapproved of his methods after he took over. Doubt that she'd see eye to eye with Cable.