What is the general ethos of each character when they enter a fight? Are they formally trained and thus play by the rules, so to speak? They wouldn't throw a punch in a fencing duel as an example. Do they use everything at their disposal, including underhanded tactics? Do they fight to kill? Do they fight exclusively to restrain but would never willingly or deliberately kill someone? Would they rather not fight at all and talk the enemy down, fighting only to defend themselves? Those sort of questions.
Interesting questions, I might break it down by category.
Fully Pacifist (no fight only talk)
Mostly Pacifist (self-defence or defence of others is an exception)
Oscar, Joanna, Fiona, Arslan, Iris, Ozpin
Pacifist Fighter (won't start the fight, but can fight)
Jaune, Taiyang, Hazel, Marrow, Penny, Ciel, Flynt, Summer
Neutral Fighter (willing to start the fight but absolutely does not kill)
Ruby, Weiss, Blake, Yang, Pyrrha, Harriet, Tortuga, Neon, Emerald, Velvet
Willing Fighter (enjoys a fight, tries not to kill but accepts it as a possibility)
Ren, Nora, Qrow, Raven, Clover, Elm, Robyn, James, Sun, Roman, Sienna
Lethal Fighter (willing to kill)
Winter, Adam, Watts, Mercury, Vine, Ozpin, Glynda, Oobleck
Bloodthirsty Fighter (violence is their existence)
Tyrian, Marcus, Salem, Neo, Cinder, Vernal
Meanwhile the second line on this graph I'm going to just pick the characters that most exemplify these options, noting that some characters are more willing to slide up and down the scale depending on the situation and the severity of a fight (i.e. Winter would fight fair-ish in a spar, she would not in a real fight)
Weiss, Pyrrha, Arslan, Adam, Hazel, Penny
Ruby, Blake, Yang, Sun, Tyrian, Taiyang, Summer, Watts
Ren, Mercury, Qrow, Raven, Cinder, Nora, Winter