Hi again, Im sorry i started that confusion. Scott is right, i just meant that out of the fish that you wanted those are the ones that could fit in there, not the ones that could go togehter in there!
FNM i think what you need to do is decide what fish you are going to focus on and then stick with that. you seem to be set on Krib's because you already have them. Im not sure what you can add to those because I dont have any experience with them but we should focus this on what can go with them in their wwater parameters.
On the other hand if you would rather focus on something else then an entirely diffrent combo of fish can be suggested. For example if you would like a tank for the tanganikan shell dwellers we work with that, or maybe the convicts if you would prefer them.
About your ailing Krib, Im not an expert on the illnesses but from second hand info i would hazard a guess and say your male has a parasite of some kind. Or simply is not eating, I have had a couple of fish just stop eating on me recently and im still not sure why. Maybe the female is bullying him away from the food? If you can see his spine it is probably to late to save him though im afraid. Hopefully someone with more experience can come and tell me im totally wrong