Losing references with instantiate prefab

I've created a GameObject (renamed "Explosion") with three childs. Every child has a different Particle System (Smoke, Sphere and Ring) to create an explosion effect and I want auto-destroy the parent GameObject "Explosion" and all childs once all Particle Systems finished playing.

To do this I've created this script "ManagerExplosion"

 public ParticleSystem smoke;
 public ParticleSystem sphere;
 public ParticleSystem ring;

 // Use this for initialization
 void Start () {


     smoke = GetComponent<ParticleSystem>();
     sphere = GetComponent<ParticleSystem>();
     ring = GetComponent<ParticleSystem>();
 }
 
 // Update is called once per frame
 void Update () {

     if (!smoke.IsAlive() && !sphere.IsAlive() && !ring.IsAlive())
     {
         Destroy(gameObject);
     }

Using another script, I create the instance

 public GameObject explosion;

 void Start () {
     Instantiate(explosion);
 }

This is the GameObject "Explosion" and the script with the three Particle System that I've dragged

The issue is when I launch the game it Instantiate prefab correctly and all Particle Systems works but, as you can see, I lose all references Perticle Systems and the GameObject "Explosion" is not destroyed...

Obviously I get an error because there is not attached Particle System: MissingComponentException: There is no 'ParticleSystem' attached to the "Explosion(Clone)" game object, but a script is trying to access it.

So, what am I doing wrong?