The term "golden skin" likely doesn't mean literally golden metallic like skin like those aliens in guardians of the galaxy. It's kinda like if one was referring to native Americans and their "copper skin" as them actually having a hard metal skin - it's clearly ridiculous. Y'all are taking this too literally. Dalinar's wife was irali. Her skin was normal skin, maybe a different tone or shade, but it was skin. Heck, if she had metal skin, maybe he wouldn't have been able to roast her to death (Yeah I said it!)...
I think it's pretty clear after reading W&T and now rereading TLM, that the irali came to scadrial and are in Bilming. Now, whether they brought chouta or not is another story. I could just as easily see Hoid or Sigzil bringing the recipe or a host of other world travelers, some maybe unknown to us at this time.
