Here ya go:
2 - Dwarf Sumbu
2 - White Kapemba calvus
Either one or the other. My suggestion would be the Sumbu due to their smaller adult size.
2 - N. Toae - Good choice. I did a little more reading on this species. It's adult size stays small and is not overly aggressive.
The C. macrops is a nice choice, however these do best again in groups to feel comfortable and to spread out aggression. Yes!! They can and do get aggressive. I have had these on several occassions and have seen the aggression first hand.
As for the tretocephalus...one word...FORGET IT. OK so that was two words.
They attain a size of 6"+ and are highly aggressive.
Hope this news wasn't to bad. At least I didn't shoot down all your choices.