I have not seen a mod of this. They may just be using Cloud Ruler temple pieces, I'm not sure.
I don't think so. They have full Japanese-looking exteriors. Cloud Ruler Temple is just one mesh and one shape. Maybe they're retexturing a tileset already in-game, but I don't think that's the case either.
Here're are few examples:
http://www.tesnexus.com/downloads/file.php?id=14210
http://www.tesnexus.com/downloads/file.php?id=17229