Punchline isn't Asian. From an interview with Brian Bolland:
"Eddie" is Eddy Choi, who as far as I can find is an executive assistant of Jim Lee.I have no idea who Punchline is. Eddie had to send me [a] reference. The artist's work looks very manga-influenced to me. I thought maybe she was Japanese. I had to ask Eddie what was her ethnicity. He told me Caucasian. Apparently a few artists have asked that.