To me, the top pic looks like a Dragon Blood peacock; 2nd pic an Acei; 3rd pic a Demasoni; the yellow fish in 3rd pic looks like a yellow Lab; the blue barred looks like a juvenile Kenyi; the name escapes me on the last fish, but they're pretty common, so someone will know it.
The Acei, Demasoni, Yellow Lab, and Kenyi are all Mbuna cichlids; the Dragon Blood is a peacock. The general rule is to not mix Mbuna and peacocks due to behavioral differences, but many people mix them with good results. If you have plenty of caves and hides in your tank, it may work fine.
Demasoni is a dwarf Mbuna, and IMO one of the most aggressive of the African rift lake cichlids. Typically, it's a conspecific aggression, but with only one in the tank, it may become aggressive to the other fish. Most people who keep them advise having at least 10-12 together to spread aggression out. I had them a couple years ago. Started with about a dozen. Within a week, I had 7, and 6 of them had torn fins, missing scales, and in a couple cases, torn gill covers. I've heard horror story after horror story from other people who've kept them, but for every bad experience I hear about a good experience. They're beautiful fish, so if you want to try keeping them, my advice would be to get a dozen more; and good luck.