Are there any standards for fashion and military uniforms in ATLs?

I've had a few ideas for a TL with a mid 1800s POD that I'm working on in which I'd like to change the appearance of the military uniforms used by several countries but maintain public fashion trends until the early 1900s.

The ideas that I have in mind include
· Having Victorian style dress persist longer than in OTL but I'm not sure how to make top hats and frock coats more popular at that time.
· By the time of 1900 I'd like Britain to have, instead of choosing the brown khaki uniforms of OTL, an earthy red clay color for there uniforms. As well I'd like them to be inspired by the German stahlhelm (which is not butterflies away) and issue helmets which look like metal versions of the Foreign Service helmet.
· I'd also like the Japanese to be inspired by the German stahlhelm helmet and copy it design but change it by angling the neck guard outwards more and by making it longer so that it more resembles a samurai helmet. Also I'd like them to adapt bayonets shaped similar to tanto blades.
· I'd like the USA to adapt dark teal-green uniforms.
I believe that these color changes would still provide some camouflage capabilities but to support their use I'd write in my TL that there adoption is for the sake of moral, the same for the Japanese equipment.

What issues do I need to consider when trying to make these changes and what other good examples of alternate military uniforms could I look to for inspiration in the cases of other countries such as Germany, Russia, Mexico, and Brazil?
 
Is "foreign service helmet" a fancy way of saying pith helmet?
A pith helmet in the specific shape used by the British foreign service.
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When you talk about fashion, my TL actually diverges quite wildly from our fashion norms. Greater political and cultural divergence in Europe through a greater willingness to understand native cultures have born some interesting results. Men in Britain, before the revolution at least, wore their hair long and grew beards. Clothes are flowing but heavy to counteract the cold. The wealthier in society carry ceremonial swords. In France, a kind of ceremonial toga has become the norm, and some African and Arab influences have worked their way in as well. In Britain, post-revolution, clothes are less flowing and more like overalls. However the attitudes to facial hair remain, cosmetic scarring is in vogue as are tattoos. Jewellery crosses the gender gap, and though these are typically not extravagant it is still seen as important. Jewellery often signifies a role or rank in society.
 
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