Batman would get his belt, but he wouldn't get Robin. Robin and a Biju serve the same purpose; they're a separate being who helps the other person during battle. They have their own will, and thus are able to fight in ways and think in ways that the first person couldn't. Gaara without his Biju can be ranked, and if Naruto ever fights without his, he can as well.
Your right about not getting robin, I guess it's my fault for not emphasizing my intented point. In vs. and in general rankings the "rule" is that characters get all abilites and tools that they normally have in a given series. So, if your talking about naruto pre-extraction then he is ranked with his biju ( consider it as a weird case of being bipoler- There chakras at that point were completly mixed chackra includes physical apsects and spiratual, so naruto's mind and body "merged with the kyubi".
Since Naruto always has kyubi with him in fight, he gets ranked with it. If, Robin and batman were born conjourned togethor, then yes batmans and would get robin in rankings. I don't know what you read, but generally the "rule above" is considered the norm, and it exists becuase of the logic of "always having the ability with you". For example, the mutant Legion can absorb personalities from other dieing mutants, then he gets their power at the cost of sharing his consiousness with them. Even though they are indepentant counscieness, they count as legions "power" in rankings.
Again, try to think about summons, if summons count in a individuals ranking then why shouldnot jinjuurki. The stronger argument is if you count Kiba and Akamaru or Shino and his bugs, then it's a complete fallicy to believe that biju shouldnot count.
I understand your point (to an extent) , Naruto shouldnot get kyubi in a "solo" rankings, even though technically, all humans share their body with thousands of living bacteria, and without them we would die. Likewise, all chakra originates from the juubi ( and to a lesser extent the kyubi aswell) so everyone has "chakra" which is spirit and physical embodiemts of the juubi in them. In that sense, the sage made it so that all ninja on the planet are the juubi's jinjuuriki ( really the fruits but, its supposedly a part of the juubi) albeit only containing small amounts, think of Sora, the psuedo-jink.
YOU can make a list excluding jinks, but understand that by using your same logic you shouldnot use any Summons, animals, no juubi, no samahada.
While typing I just thought of a good way to explain: compare naruto's situation to Ichigo. In lists, prior to the Aizen's defeat, Ichigo always got his hollow mask powers. Even though his inner hollow had its own consiousness. Similar to Kuruma and Naruto,
