So I think I figured out my rear end noise - pretty sure that it was actually my parking brake that was sticking. When I hear the rubbing noise, I raise the parking brake a little bit and the sound disappears - I'm going to adjust the cables this weekend and see if it helps. I assume that the cables have just stretched over time.
Now I'm able to focus on other odd noises in my car. When I do a sharp turn at slow speeds, I hear the power steering pump groaning. I don't hear the belt squealing or anything, the pump is just a bit noisy. I've checked the power steering fluid level and it's right between min and max, so I don't believe it's a fluid issue.
Is this indicative that the pump is near the end of its life? Or is it related to my belts or pulleys? I'm pretty certain it's not belt or pulley related because usually the related sounds are different. The noise I hear is definitely my power steering pump groaning - I remember my old Ford Taurus' pump doing the exact same thing before it went kaput. It works fine other than being noisy - I'm just concerned that it may be putting more pressure on the lines than they should really be handling.