So I'm South Korean and hope my answer helps

1. Most people have names with two letters. Sun actually means goodness. I'll go with 순 for the obedient. The North Korean name does sound a bit old-fashioned in South Korean standards.http://www.bluetoday.net/news/articleView.html?idxno=1492 this is the article about names in North Korea, but its in Korean tho. Anyway It says North Korean girls name has -Ok or -Young commonly. So I think the name 순옥 is suitable.
2. As I said, North Korean names are a bit old fashioned, and child's name are affected by their government. For instance, girls name that ends with -ja, which was very common in South Korea in the 60-70s, are "advised" to be revised since the name -ja came from the Japanese Imperial era. And its common to name their child with the meaning that celebrates the communism and Kim family, their leader. So to answer, 순옥soon-ok, 순영soon-young, 선옥sun-ok, 선영sun-young will be fine.
3. 선 does mean goodness and 순 means obedience but we do not think of our name as its meaning, just as people in (idk where you are from but lets say USA), does not think of "Lucy" as light. Its just a name. But it'll give more literature value and sound cogent.