An even number higher than two won't help at all, two will still pair off and may kill the rest anyways. You can get 2 clownfish (the black ocellaris you mentioned and a percula would work out I think), a royal gramma, and a pygmy angelfish. That will be it for a tank that size. And you need to spread out the time between adding fish, give about 3-4 weeks in between.
BTW, don't start new threads about basically the same topic, just reply to your first topic if you have a relevant question.