it is, since hangul is phonetic, so ㄹ= l/r and ㅠ=yu so put them together and you get ryu

with Oh Sangeun, it's 오상은, the ㅇis silent when in front of a vowel, ㅗ is an O sound like "Oh" (versus ㅓ, which is an eo sound using "e' first then the "o"), ㅅis sh/s depending on the vowel (with an "a" it's s), etc etc

Not sure how it is supposed to be done for Korean, but for Chinese, different regions follow different rules of romanization.

For most Chinese of the modern era, we don't have middle names. What we have is a one-to-two-character first or given name. For Mainland China, it is customary to write the two characters together with no space between when expressed in English, e.g. Wang Liqin. For Taiwan, they separate the two characters with a dash as in Chuang Chih-yuan. For Hong Kong, the two characters are separated by a space, like Leung Chu Yan.

And before you wonder, China, Singapore, and Malaysia all use the transcription system 漢語拼音(Hanyu Pinyin, often shortened as Pinyin) with some minor differences to express Chinese characters as Latin script. Taiwan has also recently adopted the Pinyin system. Prior to that, they used the Wade-Giles system. Hong Kong, on the other hand, adopts the Eitel/Dyer-Ball system, again with some modifications.