I'm going to include two more things to the CS. Well, I'm going to add one and modify one. 

Mask: Ronin are largely an illegal movement, and most of them use at least some kind of mask, helmet or other obscuring article. If a mask is pictured in the photo ref, feel free to omit. 

Sword: I'm gonna call it optional, but I think it would be cool if se had picture refs for their swords too. To add personality. I have a lot on the pinterest board.