As for the health bar, create a Sprite and call it whatever you want (I'll be referencing it as HealthBar)
(This method I am using will make a health bar that will shrink as the enemy loses health. There are ways to make it look better but this is the easiest)
Make sure the origin point of HealthBar in the center.
Add an instance variable to Enemy and HealthBar called "id". Add a global variable called idTracker.
Make sure the enemies have an instance variable called "hp" and "maxHP". When an enemy spawns, set its hp and maxHP to whatever health it spawns with. When the enemy takes damage reduce hp but not maxHP.
Then for events:
Enemy -> On Created : System -> Spawn Object -> HealthBar (Position: Enemy.X, Enemy.Y-50), then another action -> Enemy -> Set instance variable "id" to idTracker. Then another action -> Add +1 to idTracker (This makes sure every enemy has a unique ID). Then another action -> HealthBar -> Pin to Object -> Enemy. Then another action -> HealthBar -> Set "id" to Enemy.id
Then on a new event:
If HealthBar.id = Enemy.id (this should work iirc) : HealthBar -> Set Width -> (Enemy.hp / Enemy.maxHP) * 100 (or replace 100 with whatever width the HealthBar is when full)
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Sorry if this is long or confusing. If you want me to recreate what I just typed above and send you the file, let me know.
Edit: Fixed a typo