From what I can see here, your main colours are white & red.
I put metallics aside, as they're quite "neutral", and the green gems, as they are the "details".
So I think you should leave the clothes white, the armour red, but put more details in blue ? (Like the gems, the algae on the spear, the "scarf" that holds the bow)
It would definitely stay in line with the previous unit (red & white), while adding a blueish hue to it, that could link them to their seaside background...
Good luck !