So, as previously determined, this only real issue has occurred in Windows... as it turns out, the problem was solved by installing DirectX. So, I tried that.
Failure.
After that, I threw absolutely everything at it. (ddr=gdi, windowscodecs, you name it; this was in vanilla Wine, mind you.) To no avail. The same issue as soon as the game tried to show a character.
The error messages are still exactly or nearly the same as detailed in the previous post. Sadface.