All reviews show a simple toggle switch ON/OFF. There are additional options, but I think off is off everywhere. Anything else would be rather unusual.
I asked my sales rep when I ordered and according to her the sounds can be turned off completely and the setting is stored in the driver's profile. E.g. when I drive with my key I will have them; my wife with her key won't. Not that I would put too much trust in that. Most people here probably know as much about the i4 than the typical BMW dealer at the moment.