Naruto had half of the Nine-tails and he was is able to do a tailed beast transformation, I believe it would not be impossible to incorporate another tailed beast into this transformation. He is able to freely able to use other attributes of the tailed beast like kekkai Genkai ( Ex: Magnet release rasenshuriken/ Lava release rasenshuriken)? Though he only has a sliver of the tailed beast chakra there is clear evidence stating this may become a reality, though Kurama is renowned for having an expectational amount of chakra and being able to take on five other tailed beasts. Naruto uses the shadow clone technique on a large scale and one of the main 'side-effects' Let's say for the shadow clone jutsu, is the even distribution of chakra. Naruto does this on a great scale with no drawbacks making the nine tails chakra seem nearly limitless. What I am saying is that if Naruto truly wanted he could most likely do a tailed beast transformation of another tailed beast via the shadow clone technique, and I am not limiting this to the shadow clone technique in the slightest. But I do not want to introduce the idea of an odd tailed beast chimera, I am saying this because there may be a chance this happens... It seems like a completely plausible idea, but I do not want to miss any important factors (Also if i got any of these things wrong people correct me.)