Here is a song sung by Yui Makino, the voice actress of Aroma, (yes, this is the correct Yui Makino) in an anime. Aroma will possibly sound like this?
https://www.youtube.com/watch?v=eIPFonjNIKA
The Voice Actor of Mikan (Yui Watanabe) played "Nao Yokoyama" in The Idolm@ster Movie, and here is a song sang by "Nao Yokoyama". Maybe Mikan will sound like this?