Damn this sound so funky awesome!!!
For me I think its Hamaura, Hirose, Rei, then Minami.
While they all sound so similar, I can kinda hear their unique intonation slip here and there (especially the end with Minami, and Rei with her "rough" ish intonation). I can barely hear Hirose's though.
I also think the little voice is Natsumi in the intro (the one going "daisuki")
Imma have this little preview on repeat for a bit, I love it