How to Instantiate through a list of Gameobjects?

Hello,

I am trying to build a list of gameobjects based on the units the player selects. Right now, when the player clicks a button, that unit is added to the list. When the player hits 'Go' all objects in that list are instantiated. What currently happens is that every element but the LAST 2 are instantiated. What am I doing wrong? How do i properly step through a list of objects?

Here is my code. Let me know if I need to clarify this.

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class UnitManager : MonoBehaviour {
 
     public GameObject[] units;  //Array of unit gameObjects
     public GameObject[] wave; //The current wavew of the Player's units
     public GameObject[] pathPoints; //List of Path points
 
     //Class Objects
     /*****************************************************/
     public int currentnum =0;
     private Spawner Spawner;
     private GameManager gameControl;
     public GameObject spawnpoint;
     private unitBase unitBase;
 
     private unitDatabase database;  //Database of units
     public List<unitBase> _units;
     public List<unitBase> _waves;
 
     public Queue< string > buildQueue;
 
     /******************************************************/
 
     //other variables
     public float maxBuildProgress =10;
     private float currentBuildProgress = 0.0f;
 
     private int index = 0;
 
     // Use this for initialization
     void Start () {
     
         //Add the qeue for building 
 
         buildQueue = new Queue<string>();
 
         Spawner = GameObject.FindGameObjectWithTag("Spawner").GetComponent<Spawner>();
         gameControl = GameObject.FindGameObjectWithTag("Manager").GetComponent<GameManager>();
         database = GameObject.FindGameObjectWithTag("Unit Database").GetComponent<unitDatabase>(); //Controls the units available
         _units = new List<unitBase>(); 
         _waves = new List<unitBase>(); 
 
     }
               
 
     void OnGUI(){
 
         for(int i =0; i < units.Length; i++)
         {
             if(GUI.Button(new Rect(Screen.width/20, Screen.height/12*i, 200, 30),"Build  " + _units[i].unitName)) //Did player click unitt button
             {
                 //First check the wave capacity
                 //If the unit will not exceed the capacity of the wave, Check the money
 
                     if(gameControl.unitCount <=  gameControl.waveCapacity)
                     {
                         if(gameControl.PlayerMoney >= _units[i].unitCost)
                         {
                         gameControl.PlayerMoney -= _units[i].unitCost;
                         //sPAWNER handles the creation of the base mesh/gameobject
 
                         //Add units to list
                         _waves.Add(_units[i]);
                         //Add the unit to the map as agame object
 
                         gameControl.unitCount += _units[i].unitSupply;
                         //Spawner.Spawn(units[i]); //Spawn the unit that the player clicks on (I)
 
                         //Need to only instantiate on button press
 
                     }
                     }
                 }
 
         
             }
 
         //Instantiate  the unit in the wave
 
         if(GUI.Button(new Rect(600, Screen.height/12, 200, 30),"Go"))
         {
 
             BuildStuff();
 
             //Reset the Wave back to 0
         
             }
 
 
         }
 
     void BuildStuff()
     {
         for(int j= 0 ; j <= _waves.Count; j++)
         {
             
             
             GameObject newUnit = ((GameObject)Instantiate(Resources.Load(_waves[j].unitName), spawnpoint.transform.position, spawnpoint.transform.rotation)) as GameObject;
             //Need to iterate
             _waves.Remove(_waves[j]); //Remove the units in wave
             
             newUnit.SendMessage("SetPathPoints", pathPoints);
             
         }
 
         _waves[0]= null;
 
     }
 
     
 }