Any parameter supported by devices via configuration file can be overridden with replacement variables. There is not a set list since they are user defined.
If you are asking for a listing of parameters available along with meaning and valid values, as far as I know a list isn't available.
I do recommend using this guide for setting up User-Defined Overrides. It should help in finding and setting device parameters.
It may help to know what you are trying to accomplish. Is there a specific set of settings that you want to override? Are they not included in the AP Group/WLAN screens?