#1 is not an M. johnjohnsonae of either sex. Both sexes start out silver with a very distinct reddish-orange checkerboard pattern. The females stay thay way and males turn completely blue. I can't tell you what it is, but its not an mbuna of any species. Likely a hap of some sort (possibly a Lethrinops species).
#2 is indeed a Sc. fryeri and its a male.
#3 is very likely a Metriaclima estherae (Red zebra) probably females, but if it is small yet, it could just be a young male.
#4 is a man-made peacock hybrid. They have many names Strawberry, Drangon's Blood, Sunburst, Golden, etc.