Question 1. The Tsunade NPC will have three things to do: 1. you can craft skillbooks based on the materials that you can farm from instances. Keep in mind, I believe there needs to be more skillbooks introduced before this happpening as the odds of skillbooks are higher for the weaker ninjas and I think we need more so we won't see this until more ninjas get skillbooks. You c*so use skillbooks you have in your inventory to craft other skillbooks. Crafting is random and certain materials lead to certain skillbooks. Materials such as "akatsuki ring" will increase the chance for skilbooks from akatsuki members. 2. You can do instances where you can farm materials said above. 3. A treasure where you can pull skillbooks and you use seal scrolls for it.

Question 3. No. They act more so as support/damage only labeled as 2nd dps due to the other ninjas capable of being the focus on the team. For example, edo roshi is a buffer for jinchurikis.

Question 4: Don't see that happening soon as based on the trend of non-game changing ninjas will get those skill trials. Also, those ninjas like Ay, edo deidara, and kakuzu will need the orange potions which is not available in events and will cost a lot once they come alongside its protection item.

What I'm really surprised is no one mentioned the wandering merchant in North Konaha. I mean i figured people love ninja frags....

Having access to event ninjas in a similar fashion as how black market merchant functions would never happen here unless the markup on the prices are on average higher.