How to Find GameObjects after Scene Load

So I've been trying to load a scene additively (which has been working) and use one of my scripts from the first scene to find references to GameObjects and stuff in the second scene, the scene to be loaded. My simplest example is a reference to the player, which is marked with the tag "Player". Using GameObject.FindGameObjectWithTag("Player") worked fine (didn't return null) before I introduced this scene loading stuff into the mix.

But now, I try to load the second scene with SceneManager.LoadScene(..) and then use GameObject.FindGameObjectWithTag("Player"), which I want to find the player object that's in my second scene.

The problem seems to be that the GameObjects from the new scene are not being taken into account until a frame or two afterwards, which is annoying because if I wait a frame or two to initialize my reference variables to GameObjects, all my scripts in the second scene have already called Awake and Start, and you can only imagine how much red I saw (Null exceptions among other ones...).

So here's 2 things I tried, both of which didn't work:

 public void Start() {
     SceneManager.LoadScene(1, LoadSceneMode.Additive);
     GameObject g = GameObject.FindGameObjectWithTag("Player");
     //g is null.. The GameObject is clearly tagged "Player" in the next scene, however.
 }

And also this:

 public void Start() {
     SceneManager.sceneLoaded += (scene, mode) => {
         GameObject g = GameObject.findGameObjectWithTag("Player");
     };
     SceneManager.LoadScene(1, LoadSceneMode.Additive);
     //... After the scene loads, the event is fired, g is STILL null :(
 }

So my question is: How I can find my player GameObject (which exists in the second scene that I load manually through code) immediately after loading the second scene, but before the second scene's objects get Awake and Starts called? (At least before their Starts would be amazing)