How to Allow Caller Who Can Call You During "Alarms Only"? I am using Android 6.0. 
I would like to allow my mother call me also when the mode "Alarms only" is active. I have her in Starred contacts i.e. priority list. She calls me to double verify that I wake up in some mornings. 

I would like the caller can vibrate your phone even in the Alarms only mode. 

How can you setup a caller who can call and disturb you by vibration during the mode Alarms only?
You can use Tasker in this case. Although I tried so, I still couldn't come up with a non-root method.

Follow these instructions:


Profile: Event &rarr; Phone &rarr; Phone Ringing: 


Caller: A single Contact &rarr; choose your contact
Priority: Highest


You can add multiple contacts there. It is not relevant here whether your contact is a starred contact or is allowed in Priority mode's list. 
Task: (Actions): 


Code &rarr; Run Shell:


Command: settings get global zen_mode
tick Use Root
Store Output In: %ZenMode

Task &rarr; If &rarr; Condition:


%ZenMod eq 2
Or
%ZenMode eq 3

Alert &rarr; Vibrate &rarr; Time: 1000 
Task &rarr; Wait &rarr; Seconds: 2
Task &rarr; Goto:


Type: Action Number
Number: 3



The first action stores the status of Do Not Disturb mode. The second action checks whether the device is currently in Alarms only or Total Silence mode. (Remove %ZenMod eq 2 if you don't want to be disturbed during Total Silence mode). If yes, then when the call from that particular contact comes in, the device will vibrate.  You can customize the settings for Vibrate and Wait action. Their job is to vibrate the device then wait for few seconds. The use of Goto causes the task to follow the same vibrate and wait cycle for infinite times. 
Profile: You need to setup two contexts. See How to create a profile with multiple context in Tasker? for related help.


Event &rarr; Phone &rarr; Phone Idle &rarr; Priority: Highest
State &rarr; Tasker &rarr; Task Running &rarr; Name: select the task you assigned to first profile - the same task meant to vibrate the device

Task: (Actions): Task &rarr; Stop &rarr; Task: select the task meant to vibrate the device


This profile would make sure that the vibration stops only when either the incoming call is dismissed by yourself or ends up as a missed call simply because the caller  dismissed the call from their end or you didn't pick up the call resulting in timeout.


Profile: 


Event &rarr; Phone &rarr; Phone Offhook &rarr; Priority: Highest
State &rarr; Tasker &rarr; Task Running &rarr; Name: select the task you assigned to first profile - the same task meant to vibrate the device

Task: (Actions): Task &rarr; Stop &rarr; Task: select the task meant to vibrate the device


This profile makes sure that the vibration stops once the call is picked up by you.

Try it. It worked on my unofficial CM13.