I would do 4-5 different species, 1m/4f each, unless you pick an above average aggression mbuna species like melanochromis or tropheops. I would also only do one species of peacock per tank, since the females mostly look the same and have a high risk of crossbreeding. Being a 4ft I would stick to smaller haps, 7" or smaller and avoid mixing haps and peacocks with most mbuna.