Well, NG characters will defy authority figures when they feel these figures are in the wrong, but they are usually not openly hostile towards them. CG characters have a generally negative view of authorities, even when they are obviously doing good. NG characters try to keep casualties to a minimum, but will spill a little blood if need be. CG characters wish to cause as much chaos as possible for the greater good.
Future Batman didn’t intentionally kill anybody, so I’d classify him as neutral good. Admitedly, he was more chaotic than Modern Batman. That guy won’t even kill the Joker (phht).