Hi Jonno.
#1 id say probably is a young johanni
#2 isnt a mbuna its a female aulonocara. Note the more pointed mouth and larger eyes. The black spots are just bad colouration from bad breeding stocks, probably from Singapore
#3 definatly mbuna, pearlmutt?
#4 possibly a O.B estherae, difficult to tell from the picture
#5 looks like a yellow lab, rusty cross or a yellow lab with bad colouration
#6 id say thats a pseudotropheus zebra
Tanks in aquatics and pets shop labelled up as 'mixed mbuna/malawi/cichlid' are usually fish that they have adopted and cant id. its very naughty to sell a fish under a name when you dont actually know its that fish. Trust me i work in one.
And yes, fish in these tanks can be hybrids because generally they come from peoples mixed mbuna/malawi aquariums.
hope that helps
Char