How big are your Kigoma at this point? Are they wild? Is there something you have in mind?
There are a lot of possibilities. Depends somewhat on whether you want to stay in the same lake, same continent, or doesn't matter. Generally what you want are fish that aren't so small as to be easily eaten and not fin nippers, hyper active, or overly aggressive. Cyphotilapia vary in temperament, so some people get away with exceptions, like small Tanganyikans (neolamps, for example). It means odd combinations can work sometimes, but what works for some doesn't work for everyone.
I'd rule out tropheus, mbuna, and larger, aggressive new worlds-- some people attempt them with mbuna or trophs, but they're on the overactive side for fronts and tend to nip the long fins fronts develop. Aunonocara are hit and miss. I've seen (or had) some haps work, they can also be hit or miss according to species or individuals. I've seen altolamps work. Placidochromis phenochilus have worked for some. I bred O. lithobates "Zimbabwe Rock" for a while and kept some with my kaps at times, and they worked for me. I've seen some Tanganyikan featherfins work.
Like I say, lot of possibilities. Some usually work, some are hit and miss, some are a bad idea.