- No it is not possible to play a sound on remote notification unless you have it on Main bundle. Check Apple document
For remote notifications in iOS, you can specify a custom sound that
iOS plays when it presents a local or remote notification for an
application. The sound files must be in the main bundle of the client
application.
- Even if you add a sound file on your main bundle , that file can not be longer than 30 seconds
Custom sounds must be under 30 seconds when played. If a custom sound
is over that limit, the default system sound is played instead.
I hope it may help you.
solved Play notification sound using URL