I mean idk how strict korean idols are versus JP idols on the 'no dating' thing but i imagine a 'kiss scene' would be allowed b/c it's acting and all lol and prolly an 'innocent kiss' unless for some reason the writer writes some hardcore fanservice making out/french kissing with tongue or so XD
"Can you play the piano?" I mean i'm sure /some/ actors are capable but like with stunt work i imagine most would fake it or so lol or at an angle where you wouldn't see his hands and them adding in the song after