Hi 21-lancer,
well, you can check out the requirements on the cargolux or interpersonel website. Type rating is not required, but you need some exp. beforehand.
500 h fastjet is probably not enough, but maybe get a job on shorthaul first, anyway, for Cargolux, (and it shows everyday!) you need stick and rudder exp. before you join, coz here you don't learn that anymore!
Otherwise I see no reason why you couldn't join and run a smooth career!
Anyway, good luck and all the best!
WOB