OrgLaw V authorises "election laws", even though they're not mentioned in OrgLaw VII.3, so OrgLaw VII.3 cannot be a definitive list. Since OrgLaw IV both mandates that parties win seats, but that individuals hold seats and vote in the Cosa, the question of how parties assign seats to individuals must come under election laws.
And that's excluding the whole question of whether OrgLaw VII.3 is a list of "permitted topics for legislation" or "topics on which only the Ziu may legislate, not the provinces". If you believe the former, it doesn't actually include (for example) criminal law. Half of El Lex would disappear overnight.
IX.6 is pretty clear: "All powers not vested in the Kingdom by this Organic Law shall be vested exclusively in the Provinces." It's a very old provision of the OrgLaw, too.
The breadth of things covered by VII.3 is broad. "Commerce" covers a ton, for example. But again, this has never been litigated. If someone tried to defend themselves by saying that the Ziu couldn't create a criminal code, but only the provinces could, maybe it would get struck down, or maybe the judge in question would find that general criminal provisions would fall under "[t]he defence of the Kingdom, and parts thereof" or the provisions that cover inter-provincial stuff. Hard to say, since it would depend on the crime.