Spelling consistency 

Landwehr or Landwehr? - I think the latter as it's not an English word.

Cuirassier or cuirassier? - I think the former as there have been cuirassiers back to the English Civil War.

Carabinier or carabinier? - I think the latter as it's not an English word.

La Haye or La Haie? - I think the latter for consistency with the map.  

Zieten or Ziethen? - I think the latter for consistency with the map.  

Regiment / regiment, Brigade / brigade, Corps / corps - we are all over the place with this. I think it should be uppercase when describing a specific formation (2nd Brigade) but lowercase when describing one generally (Lobau's corps, but VI Corps).