Amplifier Feedback Gain
I've finally figured out what I was doing wrong. To see how I got the correct answer for the midband gain, look at the edit at the bottom of my question. As for finding wfL, it turns out 66.7 was the correct answer, I just hadn't converted it from radians/second to hertz. 66.7rad/s = 10.61Hz, which is the correct answer.