EIR waist belt was leather, but usualy covered with square metal plates which were then embossed, tinned, silvered, etc. to individual taste. The belt was worn around the outside of the mail, however the mail was "bloused" over the belt a bit to relieve weight on the shoulders.
If the armor was mail, the edges of the shoulder reinforcement could be leather edged. Neck was protected by a scarf to prevent chafing.
Sword scabbard was died leather over wood,(your choice for color) but featured metal protection at throat, waist, and tip.
Helmets could be either bronze or iron, depending on the type of helm, one material may be more prevelant depending on time and region of manufacture. Iron helmets may have bronze, or silvered trim.Rivit heads may be "nielloed" in red. Again, it may be that embellishment was individual….You need to google EIR helmets to expand your data base so you can decide what you prefer.
The bronze in this period tended to be closer to brass in color..but age, wear, condition may modify that to a degree.
For quick reference you may want to visit other manufacturers sites and look at their galleries.
Lastly, legionaries, apparently decorated their gear to taste, so this allows great latitude in your painting. You will probably get a hundred differnet opinions on this topic. Do some more research and have fun with it. They are your figures after all. Nobody knows all the answers, your choices will have as much validity as anyone elses.
Regards
