My issue with that kind of justification for not including those facial types is that it means a lot of players can't make characters that look like them. I love lore, I believe that lore considerations should be an important factor in both the story and mechanics of a game. But I think that those considerations should come second to player engagement and enjoyment. So having more diverse facial features within the game should just be a thing so long as it doesn't break the world. And really, allowing you to make a character that looks like they're from another country than the Sword Coast wouldn't really break the world. If their equivalent of Africans in the setting were for some reason residing in some otherworldly plane and haad been absent for centuries then yes, I think you could make a better case for not including corresponding facial features (Though personally I don't think that would be a satisfying case). But here they're just from other countries, it can be handwaved away with ease, it just doesn't have to be mentioned. Yes I'd love if you could dig into the culture of your character in that case but I don't think there needs to be deep justification. Just do it because it'll let more players see themselves in the game and it won't actually matter from a lore perspective because anyone who would find it incongrous just doesn't have to use those features.