I’m not really seeing the connection between Kara and Morgan Edge. I could see Edge as a Lois Lane or a Clark villain, but not Kara. Sort of a corrupt businessman who manipulates the media. But he would essentially be a poor-man’s Luthor.
I think that you will see Kara’s origin touched on in WoT, so it will probably follow that story more closely. If Krem isn’t the villain, it’ll definitely be some space-villain, given the setting of the story.