Messaging apps no longer work right after last update - Galaxy S8 Plus I updated 2 days ago.  Samsung Galaxy S8+    REV1.0 

Now I no longer receive message notifications on my lock screen
The field to set the individual SMS/Message tone has disappeared as well
and ALL messages have the SAME sounds now. 
I have no longer the option to  "Add a field" in the message apps either

Notifications are all turned on! 

I use the Android message app and the Verizon message app.
It is Samsung's Oreo update.  They removed the feature.  Complain to them. The more that complain the more chance the will fix it.