I think the more dominate/aggressive Genicanthus angel will make the other male revert to female colors...this has happened with Bellus, Lamarck and Spotbreast angels in my tanks over the past 5 yrs.
I really wanted the Zebra, so I got rid of my male Bellus and Lamarck angels...have had Zebra with 2 female spotbreast and female Bellus for past 2 yrs, without problems