1: that fight with hisoka was more about gon getting his hit back from the hunter's exam. sure, he used some cleaver moves but no one expected him to win, mostly because he was still a newb when it came to nen combat. so it still mostly just throwing hands with hisoka.
2: killua's fights tend to rely upon tactics than gon, when he can't outspeed his foes and insta-kill them, like when he was fighting with the twins and their dart game and had to use his nen ablity in a new way to overcome it.
3: kurapika has only been in one real fight in the anime, against uvogin and that was just showing off how utterly dangerous he was against members of the phantom troop. these days, he's had to use his chains in different ways due to the nature of the succession war arc. and he did take chrollo out for a time before hisoka found a way to free him from his chain curse.