Poor man's prefabs

preloadGUI.cs

public class GUIScreenLoader
	{
		private Transform container;
		private MainNavGUIConfig config; // a ScriptableObject with a list of easily editable components
                                     // it also contains a GUI Scene reference, for more control over
                                     // resource loading.

		public GUIScreenLoader(MainNavGUIConfig config, Transform container)
		{
			this.config = config;
			this.container = container;
		}

		public void LoadViews()
		{
			MonoBehaviourBridge.instance // used to avoid creating unnecessary MonoBehaviours whilst having acccess to the API
				         .StartCoroutine(LoadSceneAsynchronously(config.sourceSceneName));
		}

		private IEnumerator LoadSceneAsynchronously(string sceneName) {
			AsyncOperation async = SceneManager.LoadSceneAsync(sceneName, LoadSceneMode.Additive);
			while (!async.isDone)
			{
				yield return null;
			}

			config.GUIScreens.ForEach(AddView);
			SceneManager.UnloadScene(config.sourceSceneName);
			yield return null;
		}

		private void AddView(GUIViewConfig viewConfig)
		{
			var go = GameObject.Find(viewConfig.screenName);
			Debug.Assert(go != null, "viewConfig.screenName should point to an existing view instead of: " + viewConfig.screenName);
			if (!viewConfig.startEnabled)
			{
				go.SetActive(false); // There's a separate ScreenManager class used for view transitions and perf.
			}
			go.transform.SetParent(container, false);
		}
	}