Yes, they did use gasmasks, but the model in the pic is the 1915 one. that was replaced by the 1917, 1918, 1924, 1930 an 1938 model. So i seriusly doubd the germans would use a first generation gasmask in WW2 when they were already on generation 6 by then :p I have only seen the 1930, 1938 and 1944 models in WW2 pictures so far (not saying that older models weren't used, but it must have been incredibly rare)
Why do i know so much about gasmasks.... feel like a nerd now :s
i know the helmet was used in both wars.
And yes, probably the bayonet, to bad he is holding it straight to the camera :s