Instantiate a child with its tag

I’ve looked around at all the forums I can regarding this and I’m still stumped.
My goal is to instantiate a field (with a bunch of objects including 3 player spawn tiles), click on a gui button and have a character spawn on P1T (if its available), then spawn two other characters on the other two tiles.

I’ve got quite a few levels that all sit as prefabs in the same scene. Its important that the objects are instantiated because of how the level progression works. However when I instantiate one of the fields the child objects lose their tags. And when I tried to create a script on the tiles to have them change their own tags when they Awake, the scripts aren’t even components once the parent object is instantiated.

Does anybody know how I could assign them tags after they’re instantiated or have the tags stay?

And once I’m able to spawn a character is there any way I could do a simple- if tag P1 exists on the hierarchy check for P2?

public class OnCharButtonClick : MonoBehaviour {

public GameObject PlayerPrefab;
private GameObject P1Tile;

public void ChooseChar(int level)
	// button turns grey
	// button becomes disabled
	// Instantiate PlayerPrefab
	// Check if tag P1
	// if yes check if P2
	// if yes check if P3
	// if yes debug too many characters
	// if no change PlayerPrefab tag to P3
	// -Close Panel
	// if no change to P2
	// if no change to P1

		P1Tile = GameObject.FindWithTag("P1T");

	Instantiate (PlayerPrefab,P1Tile.transform.position,Quaternion.identity);



try this:

GameObject newObject = (GameObject)Instantiate (PlayerPrefab,P1Tile.transform.position,Quaternion.identity);

newObject.tag = "P1T";