This is a long fight with many stages. So I am going to break it apart piece by piece and explain them individually. Make sure to east a brawny lunch from your inventory (or other bento that jacks up health and defense on high); plus also have 2 slots dedicated to healing items. Preferably lv 4 healing items and lv 3 healing items. Slot 3 I would recommend something that recuperates chakra and the 4th slot being soldier pills for added damage. The only jutsu you can use is planetary rasengan +, but your taijutsu combo ends with a massive version of the rasengan dealing around the same amount of damage. Its good for when your low on chakra during the tailed beast fight in particular.
You can get 3 S ranks + 1 A or B and get an S rank for the entire thing. This creates room for mistakes during the fight with the tailed beasts.
Jinchuriki fight; I recommend the hero route. this fight plays like a mob battle minus the ability to use rear attacks and burst attacks. That way you only fight 3 of the jinchuriki at once and you don't have to fight the other 3 at this time. This part is not that hard and is one of 2 parts you can use healing items. So before you finish of the last one make sure to heal up; not only does this help S rank this part but makes the coming parts easier to S rank as well. I would focus on Roushi first as his attacks cover a large amount of space and diverts your attention from the other 2's attacks. If you manage to catch him a planetary rasengan while he is charging up or starting to perform his ninjutsu it will break the attack and the attack of the other 2 if they are trying to hit you. Same works for the 2 other 2 as well but isn't quite as required as it is with Roushi. You don't really have to worry that much about Utakata and his bubbles. All his attacks lack range so they are easy to dodge and the planetary rasengan either matches or sometimes rips right through. Yagura isn't much of a threat either. He has has an attack that is a bunch of coral reefs coming out of the ground; but because the attack is so obvious its easy to dodge.
Just remember to heal before you finish off the last one so you can easily S rank this bit, but try to leave at least one healing item for later. So you have room for error in one of the later fights.
Tailed Beasts Fight; this is the hardest part to S rank. You are doing back to back fights against 2 tailed beats at a time with Tobi butting in every once and a while.
2 tails and 3 tails.
This part is the 2nd easiest/hardest part of the Tailed beast fights. You fight are fighting the 2 tails and 3 tails bijuu. The 2 tails (blue flaming cat) uses fire attacks and the 3 tails (giant grey turtle) uses water attacks. Focus on the 3 tails first; he has an attack where he rolls up into a ball and rolls around the field attacking you. If you knock him out first you won;t have to deal with dodging it. Use chakra dash + to get close and then spam him with planetary rasengan +. While you are doing this keep an eye out for the 2 tails, if she gets too close she will start clawing at you; if she is not doing that then she will likely be sending fireballs your way. You can block these attacks by holding or you can dodge them using the substitution jutsu This part isn't hard per say but you will need to pay attention. If the 3 tails does get his rolling attack off you can summon Bee's help to stop him by pressing
Quick time Event (doing them correctly also slightly heals you)
5 tails and 6 tails
This is the easiest part of the tailed beast fight. Focus on the 5 tails first as the 6 tails has no range and is not a real threat. The 5 tails (the mountain goat) has 2 attacks. The first one first is a charge attack which is pretty easy to dodge. He can also get stuck on the wall for a few seconds after using this attack so its a good chance to land a planetary rasengan + or 2. Also you can use the support from Bee in order to stun the 5 tails for a few seconds so you can land a few attacks. His other attack has him go off screen and drop down on you; this is pretty easily dodge as the red shadow shows up where he is supposed to land. It follows you but keep running around and it won't hit you.
Once the 5 tails is knocked out time to focus on the 6 tails (the slug). Just chakra dash + to the slug's stomach and start pounding away. Use the taijutsu combo; press multiple times to use a version of the rasengan that does not take up chakra but has similar damage output. None of his attacks should hit you but be prepared to use the substitution jutsu just in case.
4 tails and 7 tails
This was to me the hardest part of getting the S rank. This part kept me from it for several attempts. If you managed to S rank every other part of this sequence of fights you can slip by with an A for this part (I did) but anything less and you won't get the S rank for the entire fight. What I did was I fought the 4 tails (giant red ape) in hand to hand/jutsu and used chakra charged shurikens + to break the 7 tail's projectile wind attack. While still focusing on fighting the 4 tails. Use Bee's support as much as possible to by yourself room to counterattack or recharge your chakra; hold . The chakra charged shuriken also stun whomever it hits for a tiny period of time; use this to your advantage. The 4 tails has a lava attack that you have to dodge/block/counter. He also has a blue energy attack that can be destroyed with charged up shuriken. The last thing to mention is the 7 tails is not very approachable is close range combat. Once the 4 tails is down; run back and forth throwing charged shuriken and using Bee's support to defeat her. The 7 tails also has an attack in which it summons 3 whirlwinds but these are easily to dodge.
Ultimately don't let your health drop into the 2nd bar + a touch more during this section and that would get an A rank for this section. Keep it about half down the green bar or higher in order to S rank this part.
Step 3: Kurama/Naruto vs the 6 tailed Beasts individually.
This bit is insanely easy. Just use + to use a tailed beast bomb; this takes out half of their health with 1 hit. Charge up your chakra by holding down while paying attention to the attacks from the tailed beast. If you see an attack coming just hold down to guard against the attack. This basic strategy works for all 6 of the tailed beasts during this part.
Step 4: Regular Naruto vs Tobi
Remember way back during the Jinchuriki fight I told you you to hold onto at least 1 healing item? This is the reason. That way if you some how get caught in 1 or 2 of his attacks you can heal and save your S rank. The basic strategy for this is to run around in circles around the field keeping Tobi right behind you. Once you feel comfortable to attack press + to use rasengan on him. He likely can't dodge. After attacking be prepared to use the substitution jutsu so you can escape and starting circling again. Occasionally during the fight you will be on the complete opposite side of the field from him. Use this opportunity to charge your chakra; hold . Keep doing this until his health drops halfway down his last bar. This triggers the final set of quicktime events with Naruto ultimately cracking Tobi's mask. This ends the fight; hopefully you got an S rank. If not try again and try to remember how the enemies attack and know how to deal with them. This should only take a few solid tries; it is slightly challenging but not nearly as bad as I originally thought.