Veivers, 20, is a goal kicking full back while Howarth, also 20, captained the Warriors in their 2010 academy Grand Final victory last month, picking up the man of the match award.
Wildcats Director of Rugby and Head Coach John Kear said: “We are thrilled with the acquisition of Veivers and Howarth. They are two highly acclaimed young british rugby league players who we believe have the talent, drive and hunger to succeed in the game.”
The pair have played in the last three academy Grand Finals, and Veivers also spent time on loan at Championship club Whitehaven last season.
Veivers said: “I’m happy for the opportunity to play first grade Rugby League, I didn’t have much opportunity at Wigan so I’m really looking forward to it.”
Loose forward Howarth spent time at Blackpool Panthers on a dual registration deal in 2010
Howarth said: “I’m delighted with the move; I think I needed a new challenge and I’m glad John has given me the opportunity to play Super League.”