Okay, I found a way to fix this, fr anyone else who has the same problem in the future. You have to continue on through the Deep Roads without Renn until you reach the cavern that leads to the outlook of Heidrun Thaig, where the bodies of the Legion soldiers lay desecrated. After killing all the darkspawn, you may not be able to examine the bodies, but don’t worry about that immediately. You should save and load once all of the darkspawn are dead, and Renn should be back in your party. After that, keep moving a little furter into the Thaig, until a Genlock attacks. After killing the Genlock, you will be able to go back and examine the bodies, trigger the cutscene, and move forward normally with every party member! 🙂
