Nice fish! Although the female looks very odd with that bump above her eyes and the bump before her tail. I would swap her for another one if you can, it could be any number of things wrong with her. You gave them good tank mates as far as I can tell, with the exception of maybe the mollys as they like a bit of salt in the water which the kirbs wont tolerate. In my experience with breeding mine for nearly 4 years, I can tell you that love wood in the tank and live plants. I found that I get the best color and more spawns out of mine when kept in a tank with dark colored wood, it also helps if the wood has natural krib-sized holes in it. I added some mopani wood to my tank which has caused my visual tannins to rise which they love. Some people don't like the tea-tint tannins give to the water, but the fish sure do; especially river dwellers like kribs. I can tell you that I could not for the life of me get my kribs to spawn until I made 3 changes to my tank; Planted it heavily, made cevaes/caves out of several pieces of wood (I started with 1 cave, now I have 7+ all made out of arranging pieces of wood), and did bi-weekly 50% water changes with R/O water (the water comes out of my tap at 8.2 ph so it's either the sudden lowering of nitrates or the sudden lowering of PH/dissolved solids). Oh ya, I also started keeping mine in a 20G L before I moved them up to a 29g
Great choice on the new cichlids, you are going to love them