Several fan casts I’ve seen have been casting white people in the roles. For a show that represents poc I thought a live action version should do likewise. Some of these (Iroh, Wan, etc.) are their original voice actors because they still fit the role perfectly.
Korra – Q'orianka Kilcher Mako – Yoshua Sudarso Bolin – Brandon Soo Hoo Asami – Jessika Van Tenzin – Tsering Dorjee Lin – Ming Na Wen Tarrlok – Kalani Queypo Amon – Sean Wei Mah Jinora – Chloe Luthi Ikki – Mana Ashida Meelo – Ian Chen Katara – Tantoo Cardinal Lieutenant – Ian Anthony Dale Hiroshi – Daniel Dae Kim Iroh – Dante Basco Pema – Maggie Q Aang – Neten Chokling Toph – Bae Doona Sokka – Tod Thawley Yakone – Tatanka Means Tunraq – Michael Spears Senna – MorningStar Angeline Unaloq – Jay Tavare Wan – Steven Yeun Eska – Devery Jacobs Desna – John Reddy Kya – Michelle Thrush Bumi – James Saito Varrick – Darrell Dennis Zhu Li – Nichole Bloom Raiko – Jason Scott Lee Aang – Tenzin Gyatso* Zaheer – John Abraham P’Li – Liz Cambage Ghazan – Takeshi Kaneshiro Ming Hua – Lucy Liu Kai – Partho Gupte Queen Hou Ting – Joan Chen Su Yin – Tia Carrere Opal – Tanaya Beatty Zuko – George Takei Iroh – Randall Duk Kim Aiwei – Kamal Haasan Bataar Sr. – Lou Diamond Phillips Bataar Jr. – Sam Milby Wei + Wing – Jourdan + Jeremy Steel Huan – Remy Hii Kuivra – Yuqi Zhang Wu – Ranbir Kapoor Toph – Tsai Chin
*Maybe unrealistic but the Dalai Lama himself making a cameo as Aang would be amazing.