Why are there no enemies spawning in the 2d roguelike tutorial I am doing?

I am on the 5th lesson of the 2d Roguelike tutorial and I am having the issue of all of my other game objects instantiate correctly, yet the enemies do not. It looks like the code is correct. I have retyped it several times. If I drag a new prefab directly into the Scene the sprite shows up just fine. Any ideas as to why the sprites are not showing up when Board Manager tries to instantiate them? I included the code for reference.

 using UnityEngine;
 using System;
 using System.Collections.Generic;
 using Random = UnityEngine.Random;
 
 
 public class BoardManager : MonoBehaviour {
 
     [Serializable]
     public class Count
     {
         public int minimum;
         public int maximum;
 
         public Count(int min, int max)
         {
             minimum = min;
             maximum = max;
         }
     }
 
     public int columns = 8;
     public int rows = 8;
     public Count wallCount = new Count(5, 9);
     public Count foodCount = new Count(1, 5);
     public GameObject exit;
     public GameObject[] floorTiles;
     public GameObject[] wallTiles;
     public GameObject[] foodTiles;
     public GameObject[] enemyTiles;
     public GameObject[] outerWallTiles;
 
     private Transform boardHolder;
     private List<Vector3> gridPositions = new List<Vector3>();
 
     void InitaliseList()
     {
         gridPositions.Clear();
 
         for (int x = 1; x < columns - 1; x++)
         {
             for (int y = 1; y < rows - 1; y++)
             {
                 gridPositions.Add(new Vector3(x, y, 0f));
             }
         }
     }
 
     void BoardSetup ()
     {
         boardHolder = new GameObject("Board").transform;
 
         for (int x = -1; x < columns + 1; x++)
         {
             for (int y = -1; y < rows + 1; y++)
             {
                 GameObject toInstantiate = floorTiles[Random.Range(0, floorTiles.Length)];
                 if (x == -1 || x == columns || y == -1 || y == rows)
                     toInstantiate = outerWallTiles[Random.Range(0, outerWallTiles.Length)];
 
                 GameObject instance = Instantiate(toInstantiate, new Vector3(x, y, 0f), Quaternion.identity) as GameObject;
 
                 instance.transform.SetParent(boardHolder);
             }
         }
     }
 
     Vector3 RandomPosition()
     {
         int randomIndex = Random.Range(0, gridPositions.Count);
         Vector3 randomPosition = gridPositions[randomIndex];
         gridPositions.RemoveAt(randomIndex);
         return randomPosition;
 
     }
 
     void LayoutObjectAtRandom(GameObject[] tileArray, int minimum, int maximum)
     {
         int objectCount = Random.Range(minimum, maximum + 1);
 
         for (int i = 0; i < objectCount; i++)
         {
             Vector3 randomPosition = RandomPosition();
             GameObject tileChoice = tileArray[Random.Range(0, tileArray.Length)];
             Instantiate(tileChoice, randomPosition, Quaternion.identity);
 
         }
     }
 
     public void SetupScene (int level)
     {
         BoardSetup();
         InitaliseList();
         LayoutObjectAtRandom(wallTiles, wallCount.minimum, wallCount.maximum);
         LayoutObjectAtRandom(foodTiles, foodCount.minimum, foodCount.maximum);
         int enemyCount = (int)Mathf.Log (level, 2f);
         LayoutObjectAtRandom(enemyTiles, enemyCount, enemyCount);
         Instantiate(exit, new Vector3(columns - 1, rows - 1, 0F), Quaternion.identity);
 
 
     }
 }