Using fieldOptions hook in an extension crashes or generates a fatal error.

I've come across 2 issues:

1. Using a method defined in a class created in the extension generates fatal error
2. Using API crashes the website

Steps to reproduce:

1. Create a new module
2. Create a class with a static method inside CRM/extension-short-name/
3. Call that method inside fieldOptions hook. For eg: CRM_extension-short-name_Class::method()
4. Refresh civicrm home page
5. Server error log will have an error similar to the following

Class 'CRM_Myextension_MyClass' not found in /var/www/drupal/sites/default/files/civicrm/ext/uk.co.millertech.myextension/myextension.php on line 159, referer: http://chamil.drupal.local/civicrm/dashboard?reset=1

6. Next inside the fieldOptions hook, use the API to obtain any random data. For eg:

    $result = civicrm_api3('OptionValue', 'get', [
        'sequential' => 1,
        'option_group_id' => "contribution_status",
    ]);

7. Refresh civicrm home page

CiviCRM 5.15.1
Drupal 7

Issue

For the first issue, it seems extension files are not loaded before invoking fieldOptions hook. Calling _extension-short-name_civix_civicrm_config(); seems to fix that issue.

function myextension_civicrm_fieldOptions($entity, $field, &$options, $params)
{
     _myextension_civix_civicrm_config();
    CRM_Myextension_MyClass::myMethod();

}

Could not find a workaround for the second issue