That team sounds really cool! Mei + sage Naruto is one heck of a 1-2 punch, but (Im really sorry about that but...) you have one major problem. Poor Scarlet blaze has one major flaw, everyone is tired of hearing it, but it has to be said, Root of Warrior passive completely destoys him. Most of the damage and skills that the fire main relies on is mostly ninjutsu based, his other strenght is the use of multiple debuffs, all of these are completely nullified for 2 turns by the lightning mains, plenty of time to gain a sizable advantage. I highly suggest you stay clear of Scarlet blaze for now, someday he will come back once they release the jinchuriki Han, but for now I suggest you use Azure Fang with that same team. You might also want to try Sakura sailor uniform as a switch to Hanzo, they are both interchangeable depending on the meta you are facing.

This obsession with buffing all ninjas in your line ups is preventing people from thinking outside the box. Sage naruto is an excellent ninja on his own, he has his own strenghts and can be used in many line ups that dont exclusively buff him. For example, he is one of the best delivery system for Azure fang's poison tai passive. You dont need to buff all your ninjas if you have a clear plan to victory.