CiviMail WYSIWYG not working
Based on the screenshots it looks like you've installed WP in it's own directory as opposed to the web root. 

Starting in Version 4.7.27 CiviCRM will detect if WP is installed in it's own directory 

So on new installs we will see a new section in civicrm.settings.php:

// Additional settings generated by installer:
$civicrm_paths['wp.frontend.base']['url'] = 'https://wpsub.test/';
$civicrm_paths['wp.backend.base']['url'] = 'https://wpsub.test/wordpress/wp-admin/';
$civicrm_setting['URL Preferences']['userFrameworkResourceURL'] = 'https://wpsub.test/wordpress/wp-content/plugins/civicrm/civicrm/';


Does you civicrm.settings.php have the above lines?   If this was an upgrade it would not.   The reason for these settings is that the baseurl is different for the front end and back end of a WP site if it's installed in it's own directory.