In case anyone else wonders what these options are for, I got this reply from support:

The Mix chords function –> Determines to what extent chords from the Major and minor keys will be used during the process. So you can re-harmonize using all major all minor or a mix of both depending on this setting.

Variations –> There is no concrete information anywhere that I can find, I would assume that it would be a percentage chance, are range value relating to playing an embellished or variation of a straight major or minor chord.

If you crank up both options one at a time to max you should hear a difference in playback as opposed to very minimal values entered.