Shell install attempt #2.
Okay, the back of the shell now drops all the way down, but, the front won't go all the way down and is doing and bit of a teeter-totter. I determined that the heat-shrinked, solder joints for the speaker wires is the issue. You can see that in this photo of the brown speaker wires running across the top of the speaker.

This one took some head-scratching to figure out.
I decided the wires had to come up a different way, so, the first thing I had to do was pry out the 6-pin wiring harness to allow me to remove the speaker and work on it. Then, I peeled the wires out from the slots in the side of the speaker. I then cut a new groove/slot in the corner. Like this:
