Steve, thank you so much for posting these scans. Here I will identify a few of the non-German items.
Plate 29, number 76- helmet plate for Bolivian Kurassiers, or possibly the Presidential Escort
" , number 85- Brazilian insignia (not sure of headgear type)
Plate 28, number 58- helmet plate for an Ecuadorian pickelhaube
" , number 60- 1st pattern Mexican Military Academy pickelhaube plate
Plate 34, middle row, right- pickelhaube of a Mexican Presidential Aide
Plate 36, upper left- pickelhaube of on officer of Argentina's Presidential Guard
" , upper right- Bolivian EM's Kurassier or Presidential Escort pickelhaube
" , middle row, left- Bolivian Officers' helmet as above
" , lower row, left- an example of one of Juncker's "fantasy" helmets, employing some Chilean parts
Plate 37, second row, left- As above. A correct Chilean artillery haube would have a round spike base
Plate 38, fourth row, left- 1st pattern Mexican Military Academy pickelhaube
" , bottom row, right- 'fantasy' helmet utilizing Chilean parts
Plate 39, top row, middle- Ecuadorian officers' helmet with parade condor
" , second row, left- pickelhaube for Chinese officers studying in Germany, or German officers at Chinese military academies
Plate 40, third row, left- Bolivian infantryman's tschako
" , bottom- kepi for Chinese officers
There are other plates there for pickelhauben from places like Sweden and Romania. Steve- would you be able to post pics of the cartridge pouches and belt buckles?
Cheers,
Arran.