Eri - Very airy, very light but strong at the same time. Tender. Nanjolno's head voice is something else, that control is amazing. She switches with no struggle at all. Most experienced, so no surprise there.

Hanayo - Most "processed" voice. Shikaco sounds so different in her normal voice. It's like the counterpart to Kotori, high and fluffy. Also depends on the song. 

Rin - Probably the most normal voice. You can hear how young Rippi is. Very light.