At the moment, you'll need to get additional ninjas to have an effective team. Try investing your seal scrolls in kage and hope you get Danzo or Darui. Mifune is fine too but focus mainly on either Danzo or Darui. Also, try to get ninjas that you can farm from elite instance up to 5* so you can refine fragments for Iruka.

If you get darui, the setup would be:

darui Iruka x
Hashriama Main x
x x x

Talents : 3,2,2,1,3 snake/serpent