Some are and some are hybrid from Mbuna and Malawi etc, but I am no expert.
They are "rescue fish" and I am uncertain of their origins, but I believe all fish in this tank (except catfish) are Mbuna, Mbuna hybrid to Malawi, or Malawi. The one exception is the Red Jewel ("Jingles") who is native to the Nile river et al.
The largest yellow fish (Buttercup) is supposed to be a male Red Zebra. His stripes are basically nonexistent, and there's narry a red freckle on him.
Leeloo, the blue and black fish who I believe to be the female, has the coloration normally seen on mature males of that shape. Leeloo is 1/3 the size of buttercup and carried their fry in her mouth about 5 weeks without eating. I separated them to preserve the fry, 6 of whom survive and are over 3" long now.
The progeny of Buttercup and Leeloo include the blue and black Baby Leeloo, Sister Leeloo (who shows the same pattern and shape but is light tan and pinkish stripes with no blue or black) and Little Brown Leeloo, showing the same shape and pattern but presenting dark brown stripes on tan. There are also three Baby Buttercups from that spawn, which all look much like buttercup physically, and the same bright yellow color.
No telling which are male or female at this point, as they are all young, and also hybrids who don't seem to follow the normal order of male/female coloration.