[Antisenil]

I did some testing and yes you can get the roles of players joining and when they change it.
BUT and this is a big but, the event for role changes fires everytime someone starts a teleport(enters loading screen), finishes teleport(end loading screen) or when going offline/online.
Also it seems like the role is not always directly given when a player joins for the first time.

You might be able to get around this if you save the last "real" role they had and check against it before you print a new role change message to chat, but I don't know enough about coding to figure out how to do this.