Construct has a hidden feature that automatically does a lot of this.
To use it:
Put everything that acquires a health bar into a family.
Set the healthbar to destroy at startup.
Then, at the start of layout, for each member of that family, create a health bar.
Then in another event, set the position of the health bar to family.x, family.top-howevermuch.
Construct will automatically place a healthbar at each family member. You can also use this technique to set the width of the healthbar to family variables, such as family('hp'), and construct will automatically know which instance to use.
This is actually better than the container method, as it is simpler to set up, all automatic and doesn't require a different health bar object for each sprite.