Actually there are rules for the names. The so-called "Revised Romanization" (RR), which was established in Korea in 2000.
In Viki we have been following that, except for u which English people still write as oo (although the RR says otherwise), and in some words, such as hyung and Unni, they put u instead of the proper eo (hyeong and eonni would be the proper way to write them).
I don't agree with that and I never do it whenever I'm chief editor or CM. It's confusing to follow some rules and not some others. And a slap on the face of everyone who is not English.
The only exception we all make, all over the world, is for a few very common, well-known surnames:
* Lee (normally it would be I or Yi)
* Kim (it should be written Gim)
* Kang (in RR written as Gang) and
* Park (normally it should be Bak).
Now of course, you have to find the names in Korean in order to romanize them. For this, there is nothing better than going to Han Cinema, where they have the names of the cast and character in Korean script. The romanization is not correct, but based on the Hangul it can be adapted.
I've done this for you or whoever is going to work on this series.
CAST AND CHARACTERS:
Ji Jin Hui (지진희) as Jo Jae Hui, 40 year old bachelor (마흔의 까칠 노총각, 조재희)
Yang Jung Ah (양정아) as Yun Gi Ran, Jae Hui's partner (재희 동업자, 윤기란)
Yoo Ah In (유아인) as Park Hyeon Gyu (박현규)
Uhm Jeong Hwa (엄정화) as Jang Mun Jeong, physician (내과의, 장문정)
Kim So Eun (김소은) as Jeong Yu Jin, Jae Hui's neighbour (재희의 이웃, 정유진)
Kim Byeong Gi (김병기) as Jang Bong Su, Mun Jeong's father/dentist (문정 부/치과의, 장봉수)
Jeon Yang Ja (전양자) as Kang Hye Ja, Jae Hui's mother (재희 모, 강혜자)
Im Ho (임호) as Park Gwang Nam (박광남)
Bae Min Hui (배민희) as Jo Yun Hui (조윤희)
Yu Tae Wung (유태웅) as Mun Seok Hwan, architect (건축사, 문석환)
Choi Yun Yeong(최윤영) as Su Yeong, Yu Jin's friend (유진의 친구, 수영)
Dan Ji (단지) as Mun Jeong's nurse (문정네 간호사)
Kim Mi Jun (김미준)
Heo Hye Jeong (허혜정)
Kim Hye Mi (김혜미)
Ha Hyo Rim (하효림)
Baek Yeong Hwa (백영화)
Seong Eun Chae (성은채) as Convenience store female employee (편의점 여직원)
Kim Yu Bin (김유빈)
Jang Jeong Hui (장정희)
Jang Mun Seok (장문석)
Ha Eun Seol (하은설)
Jeong Seok Gyu (정석규) as Emergency personnel (응급요원)
Gwon Sun Dong (권순동)
Lee Dal Hyeong (이달형) as Operations supervisor (작업반장)
Choi Myeong Jin (최명진)
Kim Tae Yeong (김태영)
Lee Jin Hwa (이진화)
Won Tae (원태)
Kim Sang Rok (김상록)
Seo Jun Yeong (서준영) as Kim Tae Yeol (김태열)
Hwang Eun Su (황은수)
Jeong Ji Yun (정지윤)
Choi Cheong Ja (최청자)
Bae Yeong Gak (배영각)
Jeong Jong Yeol (정종열) as -ryeon (11회 관련 건축사)
Kim Geon Mo (김건모) as Blind date man (맞선남) - Cameo
Wink (윙크) as Celebration perform group (축하공연 가수) - Cameo
Kang Seung Hui (강승희) as Celebration perform singer (축하공연 가수) - Cameo
Kang Ju Hui (강주희) as Celebration perform singer (축하공연 가수) - Cameo
Lee Jeong Seob (이정섭) as Matthew Jeong, Fashion designer (패션 디자이너 매튜정) - Cameo
Kwak Hyeon Hwa (곽현화) as Matthew Jeong's lover (매튜 정의 애인) - Cameo
Jeon Hye Bin (전혜빈) as Karaoke pub manager (단란주점 마담) - Special appearance
Hwang Eun Su (황은수) as Party woman (파티장 여자)
Lee Jang Kyeong (이장경) as Still cut (스틸컷)
Son Seong Jun (손성준)
Choi Seung Kyeong(최승경) as Kang Seok Gyun (강석균)
P.S. On some sites, the drama's title is He Who Can't Marry
Additional info about the characters on Wikipedia.
And here is a review.