How to enable component of children in instantiated prefab?

I'm following Quill18's Multiplayer FPS Tutorial and in Part 5 we have to enable some components in a instantiated player prefab. However, in my particular case, the player itself (with "MouseLook", "FPSInputController" and "CharacterMotor" scripts and such) is a children of another GO (caller Player GO).

How can I enable these 3 italicized components, since they're the components of a children object?

Bear in mind that these 3 scripts are JS, whereas the script that instantiates the player and enable these components is C#.

Below there is my hierarchy for the player GO and script that instantiates players:

     using UnityEngine;
     using System.Collections;
     
     public class NetworkManager : MonoBehaviour {
     
         public GameObject standbyCamera;
         SpawnSpot [] spawnSpots;
     
         // Use this for initialization
         void Start () {
             spawnSpots = GameObject.FindObjectsOfType<SpawnSpot> ();
             Connect ();
         }
     
         void Connect () {
             PhotonNetwork.offlineMode = false;
             PhotonNetwork.ConnectUsingSettings ("RPGVR 1.0.0");
             }
     
         void OnGUI (){
             GUILayout.Label (PhotonNetwork.connectionStateDetailed.ToString() );
             }
     
         void OnJoinedLobby() {
             PhotonNetwork.JoinRandomRoom ();
             }
     
         void OnPhotonRandomJoinFailed() {
             PhotonNetwork.CreateRoom (null);
             }
     
         void OnJoinedRoom(){
             Debug.Log ("OnJoinedLobby");
     
             SpawnMyPlayer ();
             }
         void SpawnMyPlayer (){
             if (spawnSpots == null) {
                 Debug.LogError ("No Spawn Spots avaiables. Don't Panic");
                 return;
             }
             SpawnSpot mySpawnSpot = spawnSpots[ Random.Range (0, spawnSpots.Length) ];
             GameObject myPlayerGO = (GameObject) PhotonNetwork.Instantiate("Player GO", mySpawnSpot.transform.position, mySpawnSpot.transform.rotation, 0);
             //Disable the Standby Camera
             standbyCamera.SetActive(false);
             //Enable "Sky Dome" Children of "PlayerGO" Game Object
             myPlayerGO.transform.FindChild("Sky Dome").gameObject.SetActive(true);
             //Enable Components in "Player" Children of "PlayerGO" Game Object
     
             ((MonoBehaviour)myPlayerGO.transform.FindChild("Player").GetComponent("MouseLook")).enabled = true;
     //        ((MonoBehaviour)myPlayerGO.GetComponent ("FPSInputController")).enabled = true;
     //        ((MonoBehaviour)myPlayerGO.GetComponent ("MouseLook")).enabled = true;
     //        ((MonoBehaviour)myPlayerGO.GetComponent ("CharacterMotor")).enabled = true;
     //        myPlayerGO.transform.FindChild("Camera 1").gameObject.SetActive(true);
         }
     }

Please help!