So, I thought I'd post my final setup here, as seen in the attached image. Everything fits in very nicely, and I even found a little solution for positioning a plugged-in LED. I took one of the spare clips I had ordered and bent the LED wires around it so it sits at just the right spot to be visible when the front panel is closed.
Also, funny enough, the spare 800K drive I had lying around doesn't actually work properly, so I'll have sort that out soon! In the meantime, it just feels good to have something in the drive slot area! The only other things I need to do are to find an actual bracket-like piece to mount the A/B switch onto and to get a clip of some kind to clean up the ribbon cables.