While poking around eBay looking for Animaniacs stuff, I spotted a listing for the Animaniacs Game Pack CD - which noted that it was Windows and Mac compatible. I'd forgotten that completely.
I stuck my copy of the CD in my iMac's drive, and ran the installer...and it worked perfectly. Well, as perfectly as it ever did under Windows. It insisted on resetting the display to 256-color mode, as it does on Windows, but aside from that, I had no problems at all. The Classic environment in OS X just works. Whee.