they could be a mix of yellow labs and red zebra or saulosi or god knows what? its quite common for malawis to mix with similar coloured malawis in a tank, its an unfortunate part of the hobby as pure strain fish become harder to find in lfs.
they will act like a normal mbuna just do weekly 50% water changes and fill your tank with lots of rock and feed a good quality food sprinula flake is a good option.
my honest advice would be take them back find a local breeder and get a trio or quad of saulosi 1m 3 female