I recently got a new Phone (BQ Aquaris X5 plus) and with that a new Android Version (Android 6). Before that I had another BQ Phone, but running KitKat. I'm missing a way to disable the vibrations, but still enable the Notification LED, so to be able to put it on the table without the loud vibration. The best option would be a separate setting, but if there's some way to get that with using the do not disturb mode it would be fine also.
If I enter the do-not-disturb mode, it doesn't activate the LED, if I allow priority notifications, it still vibrates.
I also found that someone advised to just turn down the volume once more after entering vibration mode, but thats triggering the do-not-disturb mode.