I'm doing research on The Conqueror for my next podcast episode in which I will examine the pros and cons of the CinemaScope era of Hollywood film making that show very easily when looking at The Conqueror. I saw on imdb (I know, awful source) that the local Navajo played many of the Mongol extras, and it made me wonder if there were other instances of this being done in this era. Unfortunately, I have not been able to find any information on this or the Navajo that were in The Conqueror. While I do see information on Navajo actors of this era, all of it is regarding their use as Native American extras, not extras of other races. Are there any other examples of this in the CinemaScope era, and where would I find resources on digging more into this topic?
Currently doing Film Studies, and all research is my own, so please take with a massive grain of salt.
My knowledge of 1950's era films only extends as far as those that are still remembered today. As such, it's important to remember that in the 50's the period piece was very much 'out' and the sci-fi B movie flick was very much 'in'. Unfortunately, this makes your question harder to answer as our data set is a lot smaller.
After doing some research the most prominent films from the 50's that featured Asian characters would be The Bridge Over the River Kwai from 1957, Akira Kurosawa's Seven Samurai from 1954, Kurosawa's Rashomon from 1950 and... well, as far as famous 1950's movies go these are the only one's that I can reliably say I know have asian characters in them.
Firstly, I think it's fair to dismiss the Kurosawa films. They're Japanese films, made by Japanese crews and fittingly all the actors are native Japanese. But of course, your question is more related to the Hollywood perspective on this issue.
Interestingly, after doing a bit more research I found that there was a character called Yai in The Bridge Over The River Kwai who was played by one M.R.B Chakrabandhu. Unfortunately, I can't remember the exact character, and after snooping around several film archive websites I can't find a single picture of the man or the character in question, so unfortunately I'm going to have to assume for the sake of the question by this man's name that he was in fact Native American and playing an Asian character.
Now, I realise this is a TINY sample set, but I think it is important to bear in mind the mindset of Hollywood in the 1950's, which is to say, irrereverant as anything. Slightly cheating here, but if you look at Breakfast At Tiffany's from 1961 the character of Mr. Yunioshi it's pretty evident that there is a strong precedent for casting directors to cast people who were not the characters ethnicity for economic reasons.
That, and racism was still very much part of the film industry at this moment in time, it's certainly not unreasonable to assume that casting directors would cast Native Americans in the role of Asians in films. I could only find one possible further example in the case of Mr. M.R.B Chakrabandhu, but knowing Hollywood, I highly doubt the cases we've both highlighted were isolated incidents. 1950's Hollywood was all about turning a profit, much as it has ever been, and it would be far cheaper to hire local Native Americans than Asian actors.
Unfortunately due to the seeming antipathy towards the Asian people in the 1950's, there doesn't seem to be many prominent examples of films that were set in Asia due to a fixation with Science Fiction. Hope this helped a little!
Edit: Typo