if you think about it Mickey, Donald and Goofy have been in fights outside KH
Donald is known for starting fights and getting bad luck, I'd say old Donald Duck cartoons have had Donald in more violent situations than anywhere else even KH. "No-one, but Donald Duck"
Many Mickey, Donald and Goofy movies have had sword fighting in. On being their vertion of the three musketiers. Now this movie was AFTER Kingdom Hearts came out I know but there were others including their vertion of the prince and the pauper.
Steamboat Willie wasn't just the first sound cartoon filled with music, I mean Pete was there for a reason, he wasn't really that nice to Mickey, if I remember correctly he punched and kicked the poor mouse.
Pete, he has had many roles but none of them show him as a very nice guy, well in Goof Troop and the Goofy movies he just didn't like Goofy but outside of there he made troube for Mickey and Donald, of course Mickey always struck back (Donald only struck back half the time).
KH isn't really very violent at all, at least not for Donald and Goofy. They stick to the Disney style violence. Theres no blood for example