As we've been shown by Sasuke however, one does not need to activate Six Paths Sage Mode in order to interact with the Truth-Seeking Spheres. It's something that signifies that he has the "power of the ten-tails" and the only feat of such a thing so it was a feat of Six Paths Sage Chakra, which is not completely unrelated, just like the last caption states Naruto's reaction speed is on par with Madara's, even though the image has nothing to do with Naruto's own speed. Your last point is very interesting however. It means that either his regular Sage Mode accompanied with Six Paths chakra is able to sense Limbo or Naruto is in fact using Six Paths Sage Mode. I'm not shut off to the idea, but it can't be the full Six Paths Sage Mode like he has with the cloak. I'm sure we can all agree that the stats of that Naruto surpasses the one without the cloak.
I'll agree, it's not completely unrelated as having Six Paths Chakra (which Sasuke has) and Six Paths Sage Mode are related, but the Databook Entry was focusing solely on a Rikudou Power associated with Rikudou Senjutsu and highlights characteristics only exclusive to Rikudou Senjutsu. The images themselves are supposed to represent what the user can do with the specific technique is being highlighted here which in this case, is Rikudou Senjutsu. While both are connected, Rikudou Senjutsu has characteristics that people with Six Paths Chakra normally do not have.
Well, Naruto couldn't have been in "Base" in the first place because his mode here:
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Is different from here:
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I also don't think it can be just regular Sage Mode along with Rikudou's Chakra as that seems to resemble this:
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Which is different than the mode he used against JJ Madara (Pre-Shinju). This is personally why it seems as if Naruto is using RSM w/o the Bijuu's Chakra. When he manifests the cloak, he's using Kurama's Bijuu Mode along with Rikudou Senjutsu which would give him superior stats overall of course.