That isn't possible. The timing from when Stop Opponent Ability would activate and when Vansaar's ability would activate wouldn't allow Stop Opponent Ability to effect Vansaar, or any other Leader.
Thats impossible i have a Ambre and my ambre is the best!but im trying to get a Vansaar
I wonder what happens if there are 2 of 2 kinds in your hand?
All are cancelled. 2 or more leaders, same or different, in one player's hand => all leaders of that player have their abilities nullified. (Already two of anysort trigger the "Cancel Leader" Bonus which -surprise, surprise- cannot be cancelled and is in fact the only thing that can cancel leader abilities.)