Remove Workflow from Features
It looks like you've tried alot of possible solutions with mixed success.

A method I'm not certain you've tried is to apply a patch to Features 2.x for Drupal7 that Provides a way to Import Views/true exportables back to the database.

This patch creates a new tab in the Features Admin area called Import if you select the items in the selected Feature to import back to the database, it will then attempt to import the exportable back to the database. Unfortunately as some users note in the thread -- you may not receive a confirmation message that it was successful or not. Recent versions of this patch may have addressed this lack of a status message -- I used this module months ago to move about a dozen features out of Features and back into plain/simple database configuration.

There is also discussion in the thread about Drush Ctools Export Bonus. But I found this module difficult to use and produced an error with (i think) field_group stuff at the time.