I used to like
Casey when I was 11 (mostly for its sound), but it's NMS these days. I think I prefer it on a boy rather than a girl. For a boy, I prefer the spelling
Casey, but there is something appealing about
Kasey to me even though it's a variant. I knew one Kaci (female), who was the sister of a friend.
If I had to choose between
Casey or
Kaylee, I think I would use
Casey /
Kasey, because there is more history with it.
I'm not really a fan of any of the spellings of
Kaylee. I met one
Caleigh, who I went to school with.