I read that Cookie Man is a nickname for one of their managers.
Yuri forgetting her lines the most... the evidence is clear

. She's just, like, borderline ADD or something. Too hyper and can't concentrate

. I don't think that's why she has less lines though, coz it's just Gee and Him Nae. She has lots in Destiny and gets a pretty big line in Dear. Mom. Although, it might be a reason she doesn't really act anymore? To me, she's better on variety shows anyway.