Cheat:
   
     Here  are  the  combinations  for  the invaders who are otherwise
unavailable. When collecting bodies:
   
     -  Invite a merchant and a pirate : a pesky little carpenter will
come with them
     -  Invite  a  general  and a wizard : an annoying messenger comes
with them
     - Invite a magic doll and a psychic : a curious little alien tags
along
     - Invite a gem guard and a swordsman : a witch comes along with 
them