[Magisk] ScottIsMyName:
Definitely not an expert in this area, but here is what I got:

taimen:/system/priv-app/ViPER4AndroidFX # getenforce
Enforcing
taimen:/system/priv-app/ViPER4AndroidFX # dumpsys package com.audlabs.viperfx
Error dumping service info: (Unknown error -2147483646) package
taimen:/system/priv-app/ViPER4AndroidFX # setenforce 0
taimen:/system/priv-app/ViPER4AndroidFX # getenforce
Permissive
taimen:/system/priv-app/ViPER4AndroidFX # dumpsys package com.audlabs.viperfx
Activity Resolver Table:
Non-Data Actions:
android.media.action.DISPLAY_AUDIO_EFFECT_CONTROL_PANEL:
89a7222 com.audlabs.viperfx/.main.MainActivity filter 5e135d0
Action: "android.intent.action.MAIN"
Action: "android.media.action.DISPLAY_AUDIO_EFFECT_CONTROL_PANEL"
Category: "android.intent.category.LAUNCHER"
Category: "android.intent.category.DEFAULT"
mPriority=100, mHasPartialTypes=false
android.intent.action.MAIN:
89a7222 com.audlabs.viperfx/.main.MainActivity filter 5e135d0
Action: "android.intent.action.MAIN"
Action: "android.media.action.DISPLAY_AUDIO_EFFECT_CONTROL_PANEL"
Category: "android.intent.category.LAUNCHER"
Category: "android.intent.category.DEFAULT"
mPriority=100, mHasPartialTypes=false

Receiver Resolver Table:
Non-Data Actions:
android.intent.action.BOOT_COMPLETED:
d524b3 com.audlabs.viperfx/.receiver.BootCompletedReceiver filter e07d193
Action: "android.intent.action.BOOT_COMPLETED"
Category: "android.intent.category.DEFAULT"

Key Set Manager:
[com.audlabs.viperfx]
Signing KeySets: 7

Packages:
Package [com.audlabs.viperfx] (1615a70):
userId=10218
pkg=Package{2a1d1e9 com.audlabs.viperfx}
codePath=/system/priv-app/ViPER4AndroidFX
resourcePath=/system/priv-app/ViPER4AndroidFX
legacyNativeLibraryDir=/system/priv-app/ViPER4AndroidFX/lib
primaryCpuAbi=null
secondaryCpuAbi=null
versionCode=2505 minSdk=15 targetSdk=21
versionName=2.5.0.5
splits=[base]
apkSigningVersion=1
applicationInfo=ApplicationInfo{118e6e com.audlabs.viperfx}
flags=[ SYSTEM HAS_CODE PERSISTENT ALLOW_CLEAR_USER_DATA ALLOW_BACKUP ]
privateFlags=[ PRIVILEGED ]
dataDir=/data/user/0/com.audlabs.viperfx
supportsScreens=[small, medium, large, xlarge, resizeable, anyDensity]
timeStamp=2017-11-17 20:44:03
firstInstallTime=2017-11-17 20:44:03
lastUpdateTime=2017-11-17 20:44:03
signatures=PackageSignatures{7f3590f [d7f1f224]}
installPermissionsFixed=true installStatus=1
pkgFlags=[ SYSTEM HAS_CODE PERSISTENT ALLOW_CLEAR_USER_DATA ALLOW_BACKUP ]
requested permissions:
android.permission.MODIFY_AUDIO_SETTINGS
android.permission.RECEIVE_BOOT_COMPLETED
android.permission.BLUETOOTH
android.permission.INTERNET
android.permission.ACCESS_NETWORK_STATE
android.permission.WRITE_EXTERNAL_STORAGE
android.permission.ACCESS_SUPERUSER
android.permission.READ_EXTERNAL_STORAGE
install permissions:
android.permission.MODIFY_AUDIO_SETTINGS: granted=true
android.permission.RECEIVE_BOOT_COMPLETED: granted=true
android.permission.BLUETOOTH: granted=true
android.permission.INTERNET: granted=true
android.permission.READ_EXTERNAL_STORAGE: granted=true
android.permission.ACCESS_NETWORK_STATE: granted=true
android.permission.WRITE_EXTERNAL_STORAGE: granted=true
User 0: ceDataInode=5767363 installed=true hidden=false suspended=false stopped=false notLaunched=false enabled=0 instant=false
overlay paths:
/vendor/overlay/framework-res__auto_generated_rro.apk
/vendor/overlay/Pixel/PixelThemeOverlay.apk
gids=[3002, 3003]
runtime permissions:

Package Changes:
Sequence number=5
User 0:
seq=3, package=com.google.android.gms
seq=4, package=org.videolan.vlc

Dexopt state:
[com.audlabs.viperfx]
Instruction Set: arm64
path: /system/priv-app/ViPER4AndroidFX/ViPER4AndroidFX.apk
status: /data/dalvik-cache/arm64/system@priv-app@ViPER4AndroidFX@ViPER4AndroidFX.apk@classes.dex[status=kOatUpToDa
te, compilation_filter=verify]

Compiler stats:
[com.audlabs.viperfx]
ViPER4Android.apk - 632
ViPER4AndroidFX.apk - 274

I then created a module, added it to the permissive script, rebooted, and verified it was there:

taimen:/etc/permissions # cat privapp-permissions-com.audlabs.viperfx.xml
<?xml version="1.0" encoding="utf-8"?>
<permissions>
<privapp-permissions package="com.audlabs.viperfx">
<permission name="android.permission.MODIFY_AUDIO_SETTINGS" />
<permission name="android.permission.RECEIVE_BOOT_COMPLETED" />
<permission name="android.permission.BLUETOOTH" />
<permission name="android.permission.INTERNET" />
<permission name="android.permission.ACCESS_NETWORK_STATE" />
<permission name="android.permission.WRITE_EXTERNAL_STORAGE" />
<permission name="android.permission.ACCESS_SUPERUSER" />
<permission name="android.permission.READ_EXTERNAL_STORAGE" />
</privapp-permissions>
</permissions>

However, it still doesn't work. I was really hopeful too.....maybe someone can double check my work.