AI☆KATSU!

Waka sings as Ichigo Hoshimiya. 

Ichigo is a cute-type idol. She has a medium to high range in her voice, and it has a nasal quality to it. She is part of the groups Cosmos, Aikatsu8, Soleil, and 2wingS.

Yuna sings as Ran Shibuki, Kaede Ichinose, Kī Saegusa, Shion Kamiya. Yuna can distinguish her voice, but it is still fairly recognizable due to its husky quality and relaxed vibrato. 

Kī is a pop-type idol. Her voice is in the mid to high range. It is very clear, and has the slightest hint of nasal.

Ran is a sexy-type idol. Her voice is in the mid-high range. She definitely has a clear vibrato to her ending notes, and a clear quality to her voice. She is part of the group Soleil and formerly part of Tristar.

Kaede is a pop-type idol. Her voice is in the low range. She uses her vibrato sometimes, and will sometimes slip into a very pop sounding voice for high notes. She is part of the groups Tristar and Magic Blood.

Shion is a cool-type idol. Her voice is in the low range. She uses very little vibrato. She usually only sings in groups. She is part of the group Powapowa-Puririn.

Remi sings as Otome Arisugawa, Yurika Tōdō, Miyabi Fujiwara.

Remi is one of the most talented singers in the cast. She sings high for Otome, low for Yurika, and in the mid-range for Miyabi.

Otome is a pop-type idol. Her voice is in the high range and can get slightly squeaky and nasally depending on the song. She is in the groups Aikatsu9 and Powapowa-Puririn.

Yurika is a cool-type iodl. Her voice is low and powerful. There is a hint of nasal on her high notes. She is a part of the groups Aikatsu8, Tristar, and Magic Blood.

Miyabi is a sexy-type idol. Her voice is in the mid to high range. She does slip more into her nasal in able to produce the sound in traditional Japanese music. She is part of the group Sweet & Soft☆Nadeshiko.

Voice references: https://www.youtube.com/watch?v=G3ddxNTOZT4 (2:43-4:11)

Eri is the singing voice of Sakura Kitaōji, Sora Kazesawa, Maria Himesato, and Kokone Kurisu.

Sora is a sexy-type idol. She sings in the medium-high range. She sounds very mature when she sings. She is part of the group Aikatsu8.

Maria is a cute-type idol. She sings in the high range. She sings very much like a baby would talk and squeaks a lot on her high notes. She is part of the group Aikatsu8. 

Sakura is a cute-type idol. She sings in the medium range. She also uses a fair amount of vibrato. She is part of the group Powapowa-Puririn.

Kokone is a pop-type idol. She sings in the high range. She has a lot of squeak and nasal in her voice. She is part of the group Sweet & Soft☆Nadeshiko. 
Sing at least 30 seconds of "Love Like Carmelize": https://www.youtube.com/watch?v=bjukG7Qz59Y

Keep in mind that if you are cast as Eri, you will need to sing as both Sora and Maria in Aikatsu8, so make sure their voices are distinct. 

Ruka is the singing voice for Hime Shiratori, Aria Futaba, Akari Ōzora. The nice thing about Ruka is that all of her characters pretty much sound the same. All of her characters except for Aria sing in the medium-high range. She punches all of her high notes forcefully for all of her characters except for Aria. 

Hime is an idol in the Flower Song Class. She sings in the medium-high range. She is part of the group S4.

Akari is a cute-type idol. She sings in the medium-high range. Akari and Hime sound almost exactly alike. She is part of the groups Cosmos, Luminas, and Skips♪. 

Aria is a student of Neo-Venus Ark. She sings in the high range. She is the only character that Ruka does not attack the high notes on.

Miki sings as Ako Saotome and Hinaki Shinjō. She has a distinct nasal sound to her voice. 

Hinaki is a pop-type idol. She sings in the high range. She is part of the groups Luminas and Passionate✮Jalapeño.

Ako is an idol of the Bird Theater Class. She sings in the medium-high range. She is in the groups Yuzukoshō and FuwaFuwa Dreamer.

Miho is the singing voice of Yozora Kasumi, Kirara Hanazono, Juri Kurebayashi, and Nono Daichi. For all of her characters, she has a distinct nasal tone. 

Yozora is a part of the Moon Beauty Class. She sings in the medium-low range. She is part of the groups S4 and SKY-GIRL.

Juri is a sexy-type idol. She sings in the medium range. She is part of the groups Passionate✮Jalapeño and Vanilla Chili Pepper.

Nono is a sexy-type idol. She sings in the high range. Her voice is very cutesy. She is part of the group  NoriNori Sisters.

Kirara is a pop-type idol. She sings in the range. Her  voice is very light. 

Kana sings as Yuzu Nikaidō, Mahiru Kasumi, Madoka Amahane, and Nina Dōjima.

Yuzu is a part of the Wind Dance Class. She sings in the medium-high range. She is part of the groups S4 and Yuzukoshō.

Mahiru is part of the Moon Beauty Class. She sings in the medium range. She is part of the group SKY-GIRL.

Madoka is a cute-type idol. She sings in the medium range and sounds slightly cuter on her high notes. She is part of the groups Skips♪ and Vanilla Chili Pepper.

Nina sings in the medium-low range. She sounds like a mix of Mahiru and Yuzu. She only sings one song. 

Sena is the singing voice of Yume Nijino.

Yume is in the Flower Song Class. She sings in the high range, and has a nasal sound to her voice. She is part of Yuzukoshō.

Rie is the singing voice of Laura Sakuraba, Rei Kizaki, and Sumire Hikami.

Sumire is a cool-type idol. She sings in the high range. She is able to sing strongly yet softly. She is part of the groups Luminas and Dancing Diva.

Laura is part of the Flower Song Class. She sings in the medium-high range.

Rei is a former model who attends Neo-Venus Ark. She sings in the low range. 

Kana is part of M4 from Aikatsu Stars. He sings in a medium-high range and has a nasal quality to his voice. 

Subaru is the center for M4 from Aikatsu Stars. He sings in the medium-high range, and has a nasal quality to his voice. 

Nozomu is a part of M4 from Aikatsu Stars. He sings in the medium range and has a slight nasal quality to his voice.