Receive notifications in FCM plugin

I’m try to introduce push notification in my Android and iOS app.
I’m using and everything works fine.
Now, I have to insert a settings panel to give the opportunity of the users to choise notifications ringtone, disable sound and unsubscribe notification.
Is it possible ? Notifications sound is different for each user, not for app.
How can I custom my app’s behaviour (closed app) when receive notifications ?