class MemberInfoEqualityComparer : IEqualityComparer<MemberInfo>
{
    public static MemberInfoEqualityComparer Instance { get; } = new();

    public bool Equals(MemberInfo x, MemberInfo y)
    {
        return x.Name == y.Name && x.DeclaringType == y.DeclaringType;
    }

    public int GetHashCode(MemberInfo obj)
    {
        return HashCode.Combine(obj.Name, obj.DeclaringType);
    }
}

static IEnumerable<MemberInfo> GetMembersIncludingBaseNonPublic(Type type, BindingFlags bindingAttr = BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static)
{
    return EnumerateTypeHierarchy(type)
        .Reverse()
        .SelectMany(t => t.GetMembers(bindingAttr))
        .Distinct(MemberInfoEqualityComparer.Instance);
}

// file: A.cs
public class A : MonoBehaviour
{
    public string aPublic;
    [SerializeField] protected string aProtected;
    [SerializeField] private string aPrivate;

    [Button] public void TestA() => Debug.Log($"Test from {nameof(A)}");
    [Button] private void TestPrivate() => Debug.Log($"Test from {nameof(A)}");
}

// file: B.cs
public class B : A
{
    public string bPublic;
    [SerializeField] protected string bProtected;
    [SerializeField] private string bPrivate;

    [Button] public void TestB() => Debug.Log($"Test from {nameof(B)}");
    [Button] private void TestPrivate() => Debug.Log($"Test from {nameof(B)}");
}

// file: C.cs
public class C : B
{
    public string cPublic;
    [SerializeField] protected string cProtected;
    [SerializeField] private string cPrivate;

    [Button] public void TestC() => Debug.Log($"Test from {nameof(C)}");
    [Button] private void TestPrivate() => Debug.Log($"Test from {nameof(C)}");
}

public class ExampleBehaviour : MonoBehaviour
{
    [SerializeField] private new Rigidbody rigidbody;
    [field: SerializeField] public Transform camera { get; private set; }
    public float light;
}