SnowPilot --
I don't know if an ATP is required or not, but I just interviewed for the freighter job and I can tell you that literally everyone in my group were furloughed airline pilots with between 6000 and 8000 hours total time. I'm certain we all had ATPs as well.
So, even if it isn't required, you'll probably need one to be competitive.
One of the first things you do in class in HKG is convert your license to a HK ATP, so you'll probably need one in order to convert it.
I'm just guessing, though.