Answered New user - API, handle user name as object

$userName = $array = [
    "first_name" => $formData->name,
    "last_name" => $formData->lastName
];
$user = $modx->newObject('modUser', array ('username'=>$formData->email));
$user->set('password', $formData->password ? $formData->password : generatePassword());
$userProfile = $modx->newObject('modUserProfile');
$userProfile->set('fullname', json_encode($userName));
$success = $user->addOne($userProfile);
if ($success) {
    $user->save();
    $newUserId = $user->get('id');
} else {
    $error = 1;
    $errortext = 'User not created';
}

$c = $modx->newQuery('modUser');
$c->innerJoin ('modUserProfile','Profile');
$c->where(array(
	'active' => true,
	'primary_group:!=' => 2,
));
$c->select(array(
    'modUser.id',
    'Profile.fullname',
    'Profile.email',
	'Profile.photo',
));
$c->sortby('Profile.fullname','ASC');
$c->prepare();
$c->stmt->execute();
$users = $c->stmt->fetchAll(PDO::FETCH_ASSOC);
echo json_encode(array("customers" => $users, "success" => "", "error" => ""));