heres a thought is it possible to DJ without being hip hop? yes eg. there are DJ's house music and even in Rock Bands (Incubus, Sublime, Linkin Park etc) but they're not hip hop
is it possible to do graffiti without being hip hop? yes i think so. scribbling random shit on a toilet wall is graffiti, however its got nothing to do with hip hop
now is it possible to rap without being hip hop? yes (Blondie, Fergie, Rage Against The Machine etc) just like pop rap
so if this is true i guess this is where the difference between hip hop and rap came from and this is the true difference between hip hop and rap
the only one i can't think of is b-boying, you can't bboy without being hip hop (unless you can think of a way)