This all sounds very confusing to me. There is no "protection system" for swords, aside from registration and export laws. If you want to wrap your sword in an old newspaper oiled with old frying pan grease as a way of preservation, there is no law against it.
So for that matter, you can make a shirasaya or a paper mache sheathe, but what do you hope to learn from it? Who will judge whether it was done correctly? I can guarantee that whatever you make, people on the internet will tell you you did it wrong.
If you want to look at best practices for conservation, or common practices for that matter, of course you can find a lot, but as it's not laws as much as many different opinions (people fight wars over the correct oil or uchiko).
From an academic perspective, I would recommend to define a research hypothesis that can be tested to some extent, and to define a scope that fits within the timelines of your project (comparing European versus Japanese "sword conservation practices" in general is way to broad).