The consolation role is only available to a player who never got selected for a given role.
This can be done a few ways, but here's an easy way. Start a 3 player game. Have one player drag only 2 people to 2 of the given roles, leaving one person unselected. Then let time run out. Those 2 players will be awarded roles from the given list. The 3rd player will be put into a matchup between the unselected given role and a new consolation role. Have the other players vote for the new role.
* This method works similarly in games with more players. I just gave you the 3-player version for an easier attempt.