Hello,
I interviewed with Cathay last year, and there were several SO interviewees in attendance with the DE FO's. I must say that all of them had well over 3000 hours total time. If you really are low time ie. below 3000 tt, I am sorry to say your chances are quite low. To answer your question regarding the FAA ATP written, I believe it does meet their requirement, but the best way to find out is to call up Recruitment and ask. They are quite friendly over there in HK.
Best of luck.