Ra's is Chinese from his father, his mother is a mystery since he erased his and his culture's history, but his mother's brother was a nomad leader roaming Saudi Arabia
Talia's mother is Arab Chinese
Their depiction varied. Early on, in the Dennis O'Neil and Neal Adams era she looks and dress more Chinese. Recently more dark middle eastern. Same with Damian. A lot of times they just go with Bruce clone, mainly white, but sometimes they want to depict him more middle eastern, sometimes dark sometimes light.
Seems like they don't really have a set look that artist have to follow and just let them do what they want. Like when Rebirth began Jim Lee drew him light, Jonboy Meyers dark. Then in the comics he's light, in the cover he's dark. Most of the time he's light, then for one issue he's dark. Back and forth back and forth.