Using AddComponent to add a Sub Class using a String

OK here I got it working with a generic type:

 void GetEquipment() where T : class, new(){
     gameObject.AddComponent(typeof(T));
 }

and you call like this:

     GetEquipment<Gloves>();

It works for me, so there is no reason it should not work for you. :)

Edit: Let's take an example. One file:

 using UnityEngine;
 using System.Collections;
 
 public class Equipment : MonoBehaviour {
 
     public Vector3 velocity;    
     public Transform _transform;    
     protected int health;
 
     public virtual void Start(){
         velocity = new Vector3(Random.Range(0.5f,1.5f),0,0);
         _transform = GetComponent<Transform>();
     }
     public virtual void Update(){
          //Some Update
     }
 }
 
 public class Gloves : Equipment {
     public int variable;
     public override void Start () {
         base.Start();
         variable =10;
     }
     
     public override void Update () {
         base.Update ();
     }
 }

Ok so we have in the same file two classes Equipment and Gloves that inherits from Equipment

Just for the example here is a third independent class:

 using UnityEngine;
 using System.Collections;
 
 public class NPC : Enemy {
     public int varToShowInTheInpsector;
     public override void Start(){
         base.Start ();
         varToShowInTheInpsector = 100;
     }
 
     public override void Update(){
                //Some stuff happening here
     }
 }

Now we have an object with another script that is not any of those above:

 using UnityEngine;
 using System.Collections;

 public class MyClass : MainClass {

     public override void Start () {
         base.Start ();
      }
 
     public override void Update () {
        //Many stuff here
       if(Input.GetKeyDown(KeyCode.A)) 
          GetEquipment<Gloves>();
       else if(Input.GetKeyDown(KeyCode.B)) 
          GetEquipment<NPC>();
       else if(Input.GetKeyDown(KeyCode.C)) 
          GetEquipment<Equipment>();
     }
     void GetEquipment() where T : class, new(){
         gameObject.AddComponent(typeof(T));
     }
 }

Try that on and you will see new script popping up on your inspector. I added some public variable so that you can see that the appropriate class is created. You see how easy it gets to add any custom component?