As for the little Airi - maybe she sounds like Chisa or something because I know when I first heard Kiss me, I thought Chisa got most of the lines, but they ended up being mostly Airi's. xD I get their voices confused with each other a lot...
Keep listening to this... Everyone sounds great, but Maimai really stands out. She's really improved a lot. I love her "wow". *_* Ugh can't wait to see the dance to this.