Hi Angelar
Sorry for the delay in replying. I was hoping someone with more experience of hogs in care would answer. This isn’t really my area of knowledge and it might depend where you are keeping the hog box/es, as well.
Sounds like you have created a nice place for the hog. Many are pretty much confined to one container, I believe, when being over-wintered. Often probably a space problem with large numbers of hedgehogs needing to be cared for. But a hog shut in is probably not going to be very happy about it even it does have a little bit more space. Newspaper on the floor sounds fine to me. I assume you have an area that the hog can burrow under if it wants to – I think some people use hand towels. Although some will burrow under sheets of newspaper, towels are probably nicer for them.
Maybe you could consider spending a bit of time volunteering with the person who checked the hog over, then you could see how they manage things.
You also need to know when you can release the hog. You might find this link useful:
https://www.hedgehogstreet.org/guidance-on-releasing-rehabilitated-hedgehogs/