Dupes would only occur after you've pulled both super rares from the treasure. So you can pull if you still would like Sasuke, but again that is 800-1000 seals of ninjas that you may no longer use. Also, drawing Ay is a pretty decent pull. In the future he pretty much stomps in all 1v1 scenarios with skillbreaks.. Sasuke on the other hand dominates GNW as his skilbreaks make his mystery not only crossfield but he gets stronger everytime a unit dies. Things to consider. As of now, both of them are subpar, Ay does have the upper hand if you have samui though.

The best plan of action at this point in the game is to get Kurama or Madara as Azrielle stated. You'll get more use out of them.

If you don't have Roshi, I would strongly recommend picking him up as well.

Han and Ay the 3rd are optional. I personally do use Han more than Ay though for pvp (Sage world, matsuri, space time), but the vast majority just plug him into a ranked lineup