Hall, 28, played for Hull and Hull KR before joining Wakefield two years ago and rejected a new offer from the Wildcats in order to join the new Canadian club.
“I’m really excited about being part of a new and exciting rugby league adventure,” Hall said. “I’m fully committed to do everything possible to make it a successful one.”
Kay, 24, played in Super League for Wakefield before moving to Leigh in 2014 and has become one of the most prolific scorers in the Championship with 74 tries in 82 appearances, most of them under Wolfpack head coach Paul Rowley.
“Liam and I already have a very strong working relationship and mutual respect and, when I learned of his interest, it was a no brainier to get his signature,” Rowley said.
“I have been a big fan of Craig for several years and indeed failed in attempts to sign him previously, so I am delighted that a player who never fails to entertain will be joining the team.”