Deliverator
Graphical Hackificator
For example, compare your ART_DEF_MARBLE against vanilla. In yours, there is no kfm file reference; in theirs, they define it. As a result, the kfm file in art/terrain/bonus/sulphur is unreferenced. Therefore the kf files and freezeNNNN.nif files are also unreferenced.
I guess I am pointing out that you may have a bunch of empty kfm fields in your artdefines; not sure if this is on purpose or not.
This is intentional. Not specifying the KFM tag simply means that I don't want the bonus to be animated, i.e. it will be static on the map. I'm sure a lot of these bonuses are going to be refined and replaced in time, and a lot of the currently static ones get animations. It may be slightly better to keep the unreferenced KFMs/KFs - in case we want to use them, but I'm easy if you want to delete them to keep things clean. I have copies of everything if I do need them.