dont ever do legs and shoulders in the same workout, to be honest i dont know how u would have enough time to do both, it takes me and hour and a half to just hit legs and thats when im hitting quads and alternating between calves and hams, and shoulders i would move with ur cardio and core, to be honest ur ab routine shouldnt b that long because the bulk of getting abs is lowering bodyfat, and if ur squating and deadlifting ur core should be pretty solid