Thjs is in response to  hotchkisstank having some questions about the types of equipment that the lupines used in the last pic..

So the helmet came in two patterns, the first was a rounded cone with two holes for ears. The second pattern they modified to cuts, so that the Lupines could flat their ears under the helmet during artillery barrages. The bottom view on the far upper right shows the liner suspension which is a spring steel bracket, riveted to the shell in the middle, and holding leather pads stuffed with hair on either end.

Because of their fur, Lupines cannot use face mask type Gas masks. They needed a hood type gas respirator, It took a bit more effort to put on, but kept things reasonably gas tight. Humans could also wear this mask in a pinch, but it was not optimal, and like head wear, Human and Lupines had different equipment. Both the hood and the human face mask type, used the same Box type filter, worn in a supplimental pouch either on the chest or the side, over the Bayonet frog. The helmet can be worn over the hood.

Some Human head wear could be adapted to lupine use, such as the garrison cap and the beret. It was simply worn over one ear, and the lining has bristles inside to hold onto the fur.

There were other helmets used.
The foreign helmet has a clipped on applique front shield to protect the ears, though it was not entirely bulletproof. The helmet of the allied nation was similar to the second pattern, but the stampings had turn up son the front to protect more of the ears, and a crest on it for more rigidity. The Assault Helmet was an adaptation of a medieval war helmet, to modern manufacturing with a similar liner to the second type. All sides produced a version of this with minor variations, some with armor glass lenses.

I hope this is of some interest. A lifetime of digging through boxes of Military surplus, dating back to the first world War gives one some perspective on military hardware.