For your level, your ninjas are perfectly fine. Just a normal team of Sasuke, Kimimaro, Gnw Hinata will come a long way.

Your power though is kinda low. For a level 69 you should be having around 20k. So save your coupons for lucky board, and your refines, keys, charms etc for rebate events. Spend all your resources on power items. Don't bother with ninjas yet.

Lastly, if you are on a new server and you don't have cross server arena yet, then Sasuke, Gnw Hinata, Gnw Sakura with leech on main should be good enough to reach six paths. If you are on an older server and you get matched with a lot of broken event ninja teams, then you may not want to bother with arena yet as it will be just a waste of time without having the right ninjas to counter these teams.