Is there a way to force drush to enable a module and ignore dependencies? I'm getting exception 'Drupal\Core\Config\UnmetDependenciesException' with messageConfiguration objects (....) provided by cn_migrator have unmet dependenciesin .../core/lib/Drupal/Core/Config/UnmetDependenciesException.php:84 when trying to enable a custom migration module. I've checked the dependencies listed in the YAML files and can't see anything missing. I really need to push ahead, but can't find a way to force enabling this module.
No, you can't.

But, https://www.drupal.org/node/2655104 was committed today, and it allows you to see what exactly is missing. Try patching your site with that to see the problem.