Arx Libertatis is a launcher for Arx Fatalis that works very well with Crossover. Highly recommend running the windows version of Arx Libertatis instead of the original one. Much more stable. Here is the website:
http://arx-libertatis.org/ Arx Libertatis still requires the data files from the original game. It ran flawlessly in my emulated desktop windows xp bottle while plain Arx never quite did. Here is how to set it up:
1. Install Arx Fatalis in a windows XP bottle and make the bottle run an emulated desktop. (To emulate a desktop use Wine Configuration from the Control Panels tool. Go to the Graphics tab click on the emulate desktop checkbox and use a size like 1024x800).
2. Download Arx Libertatis from the website listed above. Download the 32-bit installer. (Tested with version 1.1.2.)
3. Select the Arx Fatalis bottle and run the Arx Libertatis installer in it (right-click on the bottle name to get the option). It will ask you to point to the Arx Fatalis directory maybe located here: C:\Program Files\Steam\steamapps\common\Arx Fatalis
4. Use the Arx Libertatis-Portable launcher and play as normal. (Some Arx Libertatis version don't include a portable you may use the normal launcher but the screen size may be strange).