Clancy, who as a player iced for Altrincham and Flintshire, will combine the role with his position as head coach of Widnes Wild.
GB are in Group A in Lausanne for their second successive year in the top flight, alongside Belarus, Canada, Czech Republic, Denmark, Germany, Slovakia and Sweden.
The 28-year-old will combine his new GB position with his role as assistant coach at Elite League side Coventry Blaze.
Grubb steps up from his position as coach of GB U18s, while Richard Hartmann will continue as under-20s assistant and Dayle Keen has been named as a new assistant coach.
Easton takes over from Martin Grubb who will take up a position with GB Under-20s, while Leach moves up from his role with the under-16s.