Laravel 5: Validating Edits In-Place

I had previously asked a question here in regards for setting up in-place editing with Laravel 5 and AJAX. I hadn't updated it because I had managed offline to figure out what was wrong with it.

While the table is capable of editing user rows in-place, I'm now trying to add validation on top of it, intending on utilizing Laravel's built-in validator. However, for some reason it doesn't seem to be working. When I try to pass in the failed validator back through the JSON, it spits out every possible error I'm checking for. It's as if the validator is treating every input as empty, which doesn't make sense, as the rest of the function is clearly taking in the inputs as intended.

The code snippets in my previous question are still mostly relevant, but there have been updates to HomeController.php, as can be seen below:

public function updateTable(Users $users){

    $user = request()->input('user');

    $first_name = request()->input('first_name');
    $last_name = request()->input('last_name');

    $validator = Validator::make(request()->all(), [
      'firstName'                     => 'required|alpha',
      'lastName'                      => 'required|alpha'
    ], [
      'firstName.required'            => 'You need to give a first name!',
      'firstName.alpha'               => 'A first name can only contain letters!',
      'lastName.required'             => 'You need to give a last name!',
      'lastName.alpha'                => 'A last name can only contain letters!'
    ]);

    if ($validator->fails()) {

      return response()->json($validator, 404);

    }

    $employees->editUser($user, $first_name, $last_name);

    return response()->json($user);

}

via Chebli Mohamed