The list doesn't include some of the biggest groups. Some listed are kwans. Some are organizations.
You really should include the KHF or its preceeding organizations the Korea Hapkido Association and the Republic of Korea Hapkido Association as they were by far the largest organizations. Many of the Kwans descend from here.
The biggest early players were Ji's Sung Moo Kwan (KHA), Kim Moo Hong's Shin Moo Kwan (Korean Hapkido Association) and Myong Jae Nam's (Hapki Association). They joined to make the Rep of Korea HKD Assoc for a while.http://en.wikipedia.org/wiki/Korea_Hapkido_Federation
The earliest group was the one founded by Suh Bok Sup's Yu Sool Kwan.
The Mool Sool Kwan was founded by Won Kwang-Hwa who was a student of Suh's, then Choi then taught at Kim Moo Hong's school.
The Kido Association was another important organization fournded by Choi and eventually taken control of by the Kuk Sool Kwan group which descended from the original Kuk Sool Kwan of the KHA.
Kim Jung Yoon who had the senior most position under Choi in the original Kido Assoc. Later founded his own art called han pul.
If we were making a list for the early kwans from which other schools descend I'd say:
Yu Sool Kwan
Sung Moo Kwan
Shin Moo Kwan (Kim Moo Hong's)
Moo Sool Kwan
Korea Kido Assoc.-Dae Han Hapkido Hoe- (Choi, Ji, Kim Jung Yoon, Suh In-Hyuk and his brother Seo In-Sun)
Korea Hapkido Assoc. -Dae Han Hapkido Hyub Hoe-(Ji, Oh Se-lim, Choi Sea-oh, Kim Chong Sung, Myung Kwang-Sik, Han Bong Soo, Kim Myong Yong, Myung Jae Nam, Jung Won Sun, Kim Yong-Jin, Hwang In-Shik)
Korean Hapkido Association -Han Kuk Hapkido Hyub Hoe- Kim Moo Hong
Korean Hapki Association - Later the IHF- although Myung Jae Nam was a student of Ji's he helped form his own very large association which was directly influenced by Japanese aikido. Later he founded the less influential Hankido.
Han Mu Do is Kimm He-Young's group who was taught by Won Kwang-hwa and Ji Han Jae. He also trained with In-Hyuk Suh and represented Kuk Sool Won. He combined his knowledge of Bi-Sool, hapkido judo and kuk sool together to make Han Mu Do.
Recent light has come upon two school which claim to harken back to the orginal teachings of Choi before the curriculum was greatly enlarged by Ji Han Jae, Kim Moo-Hong and Myung Jae Nam:
Jung Ki Kwan - Lim Hyun-Soo
Yong Sul Kwan - Kim Yun-Sang