a few tips, realistically most armies of the period did not include such a variety of headgear for the infantry due to supply problems. take the Prussians, they used a single shako for all their infantry and a lot of their cavalry.
to be more historically correct with the uniform style i would make all or most of the units have the dragoon style helmet but with different coloured clothes.
Legionnaires-dragoon style helmet same uniform
formido legionnaires - dragoon style helmet, reversed uniform colours (cream main, deep red middle bit, dunno what its proper name is)
light infantry - dragoon helmet, green overalls. similar to french chasseurs
marksmen - dragoon helmet, green overalls. similar to french voltgiers
praetorian - tone down the purple to a more subdued shade, they look a bit bright
general, add dragoon helmet
overall a good mod and a great idea
+ rep