To be clear, I did nothing. I popped my phone on a charger overnight and in the morning, my wallpaper was missing, my status bar was missing, and my power button only turns the screen off and on--it won't bring up shut-down options.
I found out how to do a forced restart; did it, but to no avail.
Tried a different home screen launcher, but still no wallpaper, still no status bar. Tried adding a wallpaper--still nothing.
This next part is weirder still.
I thought I should uninstall/reinstall my home screen launcher (using default touchwiz), but the store won't show the app, my application manager won't show the app, and when I look it up on my desktop, it tells me that touchwiz isn't available for download for my phone or any of my devices. Even though it won't show up in my application manager, the menu in that app tells me that my default launcher is touchwiz, and when I try to install from the apk, it says it failed to install because of a conflict with another instance of the app.
To be fair, I doubt the launcher is the larger issue, because other launchers change nothing. But it clearly is at least a small issue. I also tried a soft reset, which did nothing. I really don't want to do a factory reset.