Kenshin - Suzukaze Mayo  
     : Kenshin is her only major seiyuu work; she has done other drama works (i.e. TV & movie) 

Kaoru - Fujitani Miki  
     : Kaoru is her only seiyuu work; she is originally a "normal" actress 

Yahiko - Tominaga Miina  
     : Many other anime works, my favorite being Karin of DNA2 and various chars in Akazukin Chacha 

Sanosuke - Ueda Yuji 
     : Many voice roles, my favorite being Amiboshi/Suboshi of Fushigi Yuugi 

Megumi - Doi Mika 
     : Many seiyuu works including Kuyou/Hanranya of RG Veda and Queen Serenity of Sailor Moon 

Saitou - Suzuoki Hirotaka 
     : Unfortunately I haven't been able to find much, other than that he was Kuno in Ranma 1/2 

Aoshi - Yasuhara Yoshihito 
     : ...

Misao - Sakurai Tomo 
     : Voice actress in several anime like Macross and El Hazard 

Shishio - Ikeda Masanori 

Soujirou - Hidaka Noriko 
     : Many seiyuu works, like Akane in Ranma 1/2 
 

Shigure - Inoue Kazuhiko 
     : Kusanagi Mamoru in Blue Seed 

Toki - Miyamura Yuko 
     : Asuka of Neon Genesis Evangelion 

Gentatsu - Sasaki Nozomu 
     : Enishi's voice, Clef of Rayearth, Yusuke of Yuu Yuu Hakusho, and many others 

Kajiki - Koyasu Takehito 
     : Hotohori of Fushigi Yuugi 

Tamano - Kosugi Juurouta 
     : Zagato of Magic Knight Rayearth, Ryden of Escaflowne 

Masashino - Yamaguchi Kappei 
     : male Ranma of Ranma 1/2 
 

Tomoe - Iwai Junko 
     : Besides being Itsuko in the RK filler eps, she has had many seiyuu roles, my favorite being Tomoyo in Card Captor Sakura and Hikari in Neon Genesis Evangelion 

Enishi - Sasaki Nozomu 
     : See Gentatsu 

Shinta - Suzuki Masami 
     : Many voice works, including Cha Cha of Akazukin Cha Cha and Haruka of H2