How to pass classes of a class to a function's parameter?

Hello and thanks for taking the time to review my question. My question: how do I pass classes of a parent class to a function's parameter?

What I HAVE, and what I WANT to do:

HAVE:

• I have a "DataContainerScript" which has several classes.

• I have a "SavingScript" which has a 'Save' function that checks if a file exists. If it does, then deserialize it (which opens it) and assign the 'fullData' variable to this deserialized file as a FullDatClass type. If the file doesn't exist, then simply create one.

• Then it checks what scene we're in, and starts the 'SaveToVariableScene' function, which saves the data shown in the script.

• Then at the end, it serializes the 'playerSaveFile' with 'fullData' and closes it.

WANT:

• So at the end of the day, what I FINALLY want to do is have a parameter of 'SaveToVariableScene' that I can feed from whichever if statement's body, which ideally would call the 'SaveToVariableScene' function with parameter: "fullData.[sceneDataContainer]"; and then 'SaveToVariableScene' function would set fullData's variables to match the GameControl's (GameControl is a static script found in every scene).

DataContainerScript:

 using System;
 using System.Collections.Generic;
 
 
 [Serializable]
 public class FullDataClass
 {
     public GameData gameData = new GameData();
     public PlayerItemsData playerItemsData = new PlayerItemsData();
     public PlayerPositionData playerPositionData = new PlayerPositionData();
     public PlayerhouseData playerhouseData = new PlayerhouseData();
     public IslandData islandData = new IslandData();
 }
 
 [Serializable]
 public class GameData
 {
     public string playerScene;
 }
 [Serializable]
 public class PlayerItemsData
 {
     public string currentlyHoldingItemName;
 }
 [Serializable]
 public class PlayerPositionData
 {
     public float playerPosX;
     public float playerPosY;
     public float playerPosZ;
 }
 [Serializable]
 public class PlayerhouseData
 {
     public bool hasPlayerVisitedThisScene;
 
     // entities
     public List<float> polygonCiviliansX;
     public List<float> polygonCiviliansY;
     public List<float> polygonCiviliansZ;
 
     // items
     public List<float> playerPoopX;
     public List<float> playerPoopY;
     public List<float> playerPoopZ;
 }
 [Serializable]
 public class IslandData
 {
     public bool hasPlayerVisitedThisScene;
 
     // entities
     public List<float> polygonCiviliansX;
     public List<float> polygonCiviliansY;
     public List<float> polygonCiviliansZ;
 
     // items
     public List<float> playerPoopX;
     public List<float> playerPoopY;
     public List<float> playerPoopZ;
 }

And SavingScript:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.IO;
 
 public class SavingScript : MonoBehaviour {
 
     public static SavingScript savingControl;
     
     void Awake ()
     {
         if(savingControl == null)
         {
             DontDestroyOnLoad(gameObject);
             savingControl = this;
         }
         else if(savingControl != this)
         {
             Destroy(gameObject);
         }
     }
 
     public void Save (bool savePlayerItems, bool savePlayerScene, bool, savePlayerPositions)
 
         FileStream playerSaveFile;
         FullDataClass fullData = new FullDataClass();
         BinaryFormatter newBF = new BinaryFormatter();
         if (File.Exists(Application.persistentDataPath + "MySave.data"))
         {
             playerSaveFile = File.Open(Application.persistentDataPath + "MySave.data", FileMode.Open);
             fullData = (FullDataClass)newBF.Deserialize(playerSaveFile);
         }
         else
         {
             playerSaveFile = File.Create(Application.persistentDataPath + "MySave.data");
         }
 
         #region Player info
         if(savePlayerItems)
         {
             fullData.playerItemsData.currentlyHoldingItemName = GameControl.control.currentlyHoldingItemName;
             fullData.playerItemsData.isAtomicPoopCompressorEquipped = GameControl.control.isAtomicPoopCompressorEquipped;
         }
 
         if(savePlayerPositions)
         {
             fullData.playerPositionData.playerPosX = GameControl.control.playerPosX;
             fullData.playerPositionData.playerPosY = GameControl.control.playerPosY;
             fullData.playerPositionData.playerPosZ = GameControl.control.playerPosZ;
         }
 
         if(savePlayerScene)
         {
             fullData.gameData.playerScene = GameControl.control.playerScene;
         }
         #endregion
 
         #region Scene save section
         // check what scene we're saving to...
         if(Application.loadedLevelName == "Scene_tier1_playerhouse")
         {
             SaveToVariableScene(fullData.playerhouseData?);
         }
         else if(Application.loadedLevelName == "Scene_island")
         {
             SaveToVariableScene();
         }
         else if(Application.loadedLevelName == "Scene_tier1_polygonCivilianComplex_entrance0")
         {
             SaveToVariableScene();
         }
         #endregion
 
         newBF.Serialize(playerSaveFile, fullData);
         playerSaveFile.Close();
     }
 
     void SaveToVariableScene (FullDataClass fullData)
     {
         fullData.hasPlayerVisitedThisScene= GameControl.control.hasPlayerVisitedThisScene;
         fullData.polygonCiviliansX = GameControl.control.polygonCiviliansX;
         fullData.polygonCiviliansY = GameControl.control.polygonCiviliansY;
         fullData.polygonCiviliansZ = GameControl.control.polygonCiviliansZ;
 
         fullData.playerPoopX = GameControl.control.playerPoopX;
         fullData.playerPoopY = GameControl.control.playerPoopY;
         fullData.playerPoopZ = GameControl.control.playerPoopZ;
     }

Thanks for any advice/answers/knowledge/help in advance! :)