This script would take forever to make.
Let alone the defence role. I'll see that being one of the main problems coding.
Healer role having problem healing players, poisoning every healer npc. You'll get kicked from the team lol.
The most I see coming close to a script for BA would be for attacker, and collector role.
Attacker role because you can simply just add a detection for the style being called, switch styles accordingly, and make it find an attackable npc. Mind you, you'll need to have it switch weapons as well.
Collector role can simply detect the egg being called, and pick up eggs accordingly.
Goodluck man.