The only RPs this would affect would be Wintreath specific ones, such as the First Tribes of Wintreath, or more appropriately Weiss' War on Many Fronts RP...hence it being laws about the region itself, not about Wintreath the Nationstates region.
All our RPs are Wintreath-specific. Again, I don't see how this would work. Laws change over time, and our storylines are spread across history and even multiple timelines. You can't just impose a set of uniform laws on prehistoric, gearpunk, post-modern, and future societies, because the culture of these settings are completely different.
Let's take a look at our RPs as examples:
First Tribes doesn't even have a "Wintrean" government or nation, as the name implies. To take one of your examples, marriage might not even have a recognizable equivalent in some of these cultures.
In Wintrean Union, Wintreath is simply the location of a UN-like body, is completely ignored as a nation for all intents and purposes, and for whatever reason is in the south instead of the north.
In From the Ashes, Wintreath is the remnant of a fallen galactic empire set in the far future, with a culture that is consequently very different from all other RPs and the Wintreath region itself.
The Wintrean government in War on Many Fronts is somewhere between feudalism and absolute monarchy, so it wouldn't even make sense to have a republican legislature governing its laws. EDIT: Never mind, I just checked "Establishment of Setting" and there appears to be Storting that developed similar to UK's Parliament. Not to mention that Weissreich's Wintreath has a rather different aging process/timeline for humans, which would obviously necessitate a different culture and a different set of laws for age limits.
Overall, it doesn't make sense to apply Storting-passed laws to any of our RPs. Each RP is set in their own situation and have markedly different Wintreaths with wildly varying cultures. And we don't have an official RP or an official timeline to write laws for either.
I'm surprised at your sudden interest in RP affairs, considering that you aren't participating in any. I get that you're the Jarl of Culture, but given that you've refrained from participating in the RP Guild and affiliated roleplays in the past, I'm not sure you have the full picture of our RP community.