noobHell, prefab arrays, GameObjects, Random Spawning

I have the basics of my game working. Random GameObjects from an array are instantiated as clones and do their thing. But, I keep reading that it's best to use prefabs, which seem limited to me because they can't pass variables very well and I'm having the hardest time making an array work with prefabs.

Does using prefabs cut down on clones and improve performance?

Here's my code, trying to make an array of prefabs from a folder, then instantiate a random one using a switch:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class GameControllerPrefabs : MonoBehaviour
 {
     //array of enemies
     public GameObject[] allenemies;
 
     //where to spawn
     float enemyrandX;
     public Vector2 enemywhereToSpawn;
 
     //when to spawn
     public float enemyspawnRate;
     float enemynextSpawn = 0f;
 
     //what enemy to spawn
     int whatEnemyToSpawn;
 
     void Start()
     {
         //This works with tags
         //allenemies = GameObject.FindGameObjectsWithTag("Enemies");
 
         //This does not work
         allenemies = Resources.LoadAll("Enemies") as GameObject[];
     }
 
     // Update is called once per frame
     void Update()
     {
         //set what to spawn when
         enemyspawnRate = Random.Range(1f, 3f);
         whatEnemyToSpawn = Random.Range(0, allenemies.Length);
 
 
         if (Time.time > enemynextSpawn)
         {
             enemynextSpawn = Time.time + enemyspawnRate;
             enemyrandX = Random.Range(7f, -7f);
             enemywhereToSpawn = new Vector2(enemyrandX, transform.position.y);
             switch (whatEnemyToSpawn)
             {
                 case 0:
                     Instantiate(allenemies[0], enemywhereToSpawn, Quaternion.identity);
                     break;
                 case 1:
                     Instantiate(allenemies[1], enemywhereToSpawn, Quaternion.identity);
                     break;
                 case 2:
                     Instantiate(allenemies[2], enemywhereToSpawn, Quaternion.identity);
                     break;
                 case 3:
                     Instantiate(allenemies[3], enemywhereToSpawn, Quaternion.identity);
                     break;
                 case 4:
                     Instantiate(allenemies[4], enemywhereToSpawn, Quaternion.identity);
                     break;
             }
         }
     }
 
 }
 

Many thanks!