Orange Zebras is a fairly ambiguous title. Are these cichlids or zebra danios or something else?
The Golden Mbuna and possibly Orange Zebras if they're the cichlids that go by this name, are too large and aggressive for this size of tank. Those fish need something closer to the 50 - 75 gallon minimum range, ideally over 100 gallons due to aggression.
It's typically not a good idea to keep neons with any cichlid other than a few South and Central American ones like angelfish, discus, apistogramma, and rams (mikrogeophagus ramirezi) as they'll eventually become dinner. It's also possible they will pester or kill the beta as well.
So basically, definitely no on the cichlids for both tank size and keeping them with these other fish. Otherwise if the orange zebras are zebra danios they should be fine. The tank size is still on the small end, I definitely wouldn't put any more fish in there, and make sure to keep up on water changes, but it should work with proper maintinence.