Sasuke is synched with the Juubi not Naruto. Naruto will likely be saved another way this scenario is more likely to play out with Sasuke. Also, it would be interesting to see Yang Kurama paired off against Yin Kurama for a final fight. So if we see Minato and Kakashi warp to Sasuke we may see some interesting stuff story wise.
I have a few issues with your ideas about Sasuke being synced with the Mazo. Firstly, we know that at this point he isn't and that Obito was endeavoring to get Sasuke to awaken the rinnegan and eventually sync with the Mazo. Now I fully admit that it is a possibility that Sasuke has Senju Dna either from Hashirama, or the Zetsu spores and may awaken the rinnegan; I fail to see how this means that means that he will summon or have anything to do with the Mazo.
Also, even if Sasuke does get get the rinnegan and decides to summon the Mazo we have no indication that summoning and syncing with the Mazo itself gives any sort of power over parts of the Mazo that have been separated for its main body. If this were the case Madara could have just summed the other part of the Mazo back if he wanted. So, if this were to happen Kishi would have to explain why Madara didn't bother summoning the Mazo's arm when it had been taken back.
Finally as far as Naruto is concerned, we have no indication that control over the Mazo Statue is necessary in order to seal a part of it within yourself. Even if this were the case, I would suspect, though we obviously have no evidence. That if Naruto were to use the arm to obtain a mini Juubi the fact that he is on good terms with all of the bijuu would make his mini Juubi more amicable to his wishes. This could be used to explain why Naruto would be near or on the same level as Juubito even if his juubi is weaker. Obito was merely subjugating a wild entity while Naruto could work in harmony with one, albeit not as powerful.