I'd agree that Sumbu Dwarf is unlikely - they are one of the least saturated comps.
As for the right I.D. - every new list we get has some new compressiceps variety - too many to keep up on. Goldhead's a good guess.
For sexing, try and get a photograph of the fish in perfect profile, and list the size of the fish. Males should be significantly higher bodied as they mature, females shorter bodied, rounder in the belly. Eventually pectoral fin length helps too. People talk about the angle of the mouth too, but I have trouble using that feature.
- Sam