In this SheepShaver build it is possible to change the mapping of the modifier keys between Windows and the Mac emulator in a keycode file. 
If enabled in the GUI, Keyboard/Mouse tab, the included BasiliskII_keycodes file will translate the modifier keys as shown below. 

The keycode function can also be enabled by editing the SheepShaver_prefs file manually. Set:
keycodes true
keycodefile BasiliskII_keycodes


The Windows Logo keys will not have a function in the emulator.

Ctrl Left --> Mac Option

Alt Left --> Mac Command

Alt Right --> Mac Option

Ctrl Right --> Mac Control
