PLEASE IS JUST MY OPINION, AND WHAT I HEARD. READ THE DESCRIPTION FOR MORE EXPLANATION
First, I really like to do this type of video, I was always interest by "who lead the chorus". And in fact when I listen Japanese Version of Korean songs, I was like "Hmmmm It's sounds different" and that why I do this video
I did this for song korean who have a Japanese version, I know I missed Boomerang/Talk, and maybe more songs...
I think for Japanese version there is some "effect" put on the vocal, so it's a little bit hard to find the real members who sing, for example The Boys it was difficult for me to find another person who sing with Taeyeon, I sometimes heard the voice of Tiffany, but I found the range of the voice sounds like Yuri
For Gee it was so difficult for the "no no no" "oh oh oh oh oh" yeah yeah yeah" "gee gee gee gee gee"... It's sounds difference every time, but I'm pretty sure that not all members record this, I think I put too much names but it's really what I heard
For Genie and Hoot, it was hard to know if Sunny sing or not, because Taeyeon's "cute voice" sounds really like Sunny, so I was "OMG IS SUNNY OR NOT?" sometimes it's easy to recognize her but for some part no...
At the end of the sentence of HOOT, (korean) I heard Tiffany sometimes, I don't know if it's my brain who had hallucinated, so I didn't write his name but seriously I through at some moments heard her
In fact I think the chorus and btw lead is not different if the chorus didn't change like CMIFC, RDR, Oh, but Mr Mr didn't change too. But for Genie, Gee, Hoot, the chorus are more "high" so it's change most than the Korean version