I dont know about other states but in Vic you are not allowed to purchase turtles under 10 cm .4 inches The turtles will need to be able to get out of the water & bask and will need uv light . Once the turtles get some size to them they will try & catch your cichlids depending on the size of the cichlids.
I tried the same thing with a hatchling long neck only to have a pair of convict cichlids kill the poor little bloke.
So if you have malawi's that aren't aggressive and you but plenty of feeder fish for the turtle it may work.
GOOD LUCK