Wow! A quick Google search shows that you absolutely nailed it! Thanks!Look pure to me.
1-2. Looks like an adult male Exasperatus (Labidochromis joanjohnsonae). Juveniles and females are attractive, maybe try to find him some females.
3-4. The common Kennyi (M. lombardoi), might be a female. Start out as cute blue juveniles, males turn yellow often dull yellow, females stay blue and often get dull unattractive as adults. Can be dominant aggressive.