I would either go for Kushina because she is very good all around or Shisui because of his mystery. Masked man does look cool but other then his mystery he is not the best in the world and you need a godo team to use with him. Kushina works and a with almost all of the ninjas and will tank very hard for you and she stacks as the battle gets longer-and kushina is the cheapest.

Good luck saving!