She shouldnt have just one or two of any of those species, all are schooling fish which should be kept in groups of 6 or more. The Congo tetra will grow too large for her tank and should definately be returned to the store, males can grow to nearly 5 inches if you include the long extensions on the caudal fin and should not be kept in anything less than 30 gallons.
I would recomend that she takes all but one species back to the shop and then keep a school of 10 of either the neons or glowlights with prehaps a few Corydoras catfish for the bottom of the tank.