When my ringtone is on vibrate, my notification sounds default to silent and there is no way to have them vibrate without turning the ringer on. Furthermore, I have no option to turn all notifications to vibrate. This is a feature my previous Samsung phones (and ALL phones!) have had! Someone help!
If you turn your volume down using the volume keys to vibrate and then pull down the volume menu from the top of the screen. Can you please send me a screenshot of the volume menu on your device when it's set to vibrate?