I'm also of Chinese ancestry and my middle name is two words hyphenated which is also how it is reflected on my passport. Oddly, my California drivers license did not allow for the hyphen (at least in the dark ages when I was 16 and getting my license for the first time).

I don't even use on UA - I think I was worried about the same problem. Now everything just shows as "Bear/OskiMR" and i don't have problems checking in, etc even if there is a middle name in the passport.