I think fur totally works for Brass Coast. You just need to think beyond big hulking bear or wolf pelts - cow/goat hides, leopard/lion patterns, crocodile skin etc.
Pleather - PVC ‘leather’ on a fabric background can easily be used in place of real leathers. It might require layering over something else to thicken it up to provide more realistic protection (IC and OOC) and to have it hold shape. It comes in many colours and can be distressed or stained to make it look more natural.
Mandala Studios have made quilted gambesons for a group in the Brass Coast before. They are totally a thing that can work in the nation: Coat of a Thousand Nails