Try the free version of Light Flow. It can change the notification sounds based on the type of notification, who it is from and much more. You can also set how often it beeps a reminder and for how long. Not to mention, you can do the same for vibrations.
https://play.google.com/store/apps/details?id=com.rageconsulting.android.lightflowlit e&feature=nav_result#?t=W251bGwsMSwxLDMsImNvbS5yYW dlY29uc3VsdGluZy5hbmRyb2lkLmxpZ2h0Zmxvd2xpdGUiXQ
The paid version gives you the ability to notify from a wider variety of apps.