Thank you both for the help!
It started raining so I had to pack up and leave finishing the project for another day. From what I've gathered from other forum posts, I will likely have to take the regulator out in order to work on it, which (according to the service manual) is a fairly labor intensive job that my rudimentary tool set won't quite be able to handle.
Interestingly, the window is working now. after pulling the metal pin, whatever was binding up the shuttle (white bit) freed, so now the window will go down and up on its own power. This is obviously not a permanent solution, as the motor sounds labored on the up-swing, but it will work until I finish my exams and can schedule time at my local self-service garage.