How to remove additional DE entries from Ubuntu Session Chooser ? How to fix login sound issue even after adding /usr/bin/canberra-gtk-play --id="desktop-login" --description="GNOME Login sound" ?

 1. To delete additional entries from LightDM:
Open this directory and delete entries you dont want:
 /usr/share/xsessions

2. To fix the login sound issue: Add this at autostart :

/usr/bin/canberra-gtk-play --id="desktop-login" --description="GNOME Login sound" --volume=2

To check sound is playing: open terminal : run this :
/usr/bin/canberra-gtk-play --id="desktop-login" --description="GNOME Login sound" --volume=2

Note: Assign a larger value at volume ( "--volume=2" ) if you still cant hear anything.