I just listened to Christina Vee's rendition of "Don't Say Lazy" and... it sounds awful.
But I don't think it sounds bad because of her
voice.
I think it sounds bad because it sounds like she's singing it at a karaoke bar. Her voice sounds "live" and the instrumental track sounds "studio" which just plain sounds dissonant.
If they replace all the songs with English versions, they
absolutely need to re-record the instrumental tracks and the vocals in studio and then
mix them from scratch.
Because the way that sounds, it is pretty horrible.
Edit: She doesn't sound too bad singing "Fuwa Fuwa Time," either.
I think I'm more forgiving of this than I normally would be because the original songs are pretty awful to begin with.
Edit 2: I'm still pissed that the supposed "rock band" Light Music Club sings pretty horrible sugary J-Pop, instead of some good Japanese girl-rock in the vein of someone like
Nanase Aikawa. I've got half a mind to splice up a lot of the live-playing footage from the series and set it all to "
Midnight Blue." (link related) (also, wow the song's actual music video is pretty fail lmao)