ok thanks for the link whoever gave me the information about the bijuu (in spanish, but that's not a problem since im trilingual) but there is a loop hole between that dudes story and his credibility, the bijuu or the japanese god doesn't exist, in reallity they do have gods but they are not called bijuu, some of them are Amaterasu, Tsukuyomi, Rajin, Fujin, Susano'o and others...and two the one that trew his credibility away was the mentioning of the 8 immortals which they do exist in CHINESE mythology not Japanese, that single fact trew his whole story away
now to naruto...he will probably have a second element that he can control wich one i don't know..i really don't like it to be water since it will be yet another disavange against sasuke, since sasuke controls fire and thunder, then naruto becoming helpless against him since he is wind and water (maybe) so i rather for him to stay just wind or maybe learn earth that will be great
also somewhere i read that Yondaime could of trained with the Toads and thats a dam good prediction, since Yondaime had the pact with Big boss frog as well and possibly new the sage secrets
now for my prediction...the figth against 8 tail bijuu will be just for sasuke to learn how to use his newly acquired badass sharingan, and defeat him eventually (he even might have control over the 8tail i mean he has control over 9 tail why not 8 (or any other bijuu)) naruto will learn how to master something i don't think he is gonna trian on becoming hermit mode but rather train with the FROG KEY that J-man left behind. and yes i believe that Naruto will obtain Yondaimes yellow flash technique. since we see a relationship between caracters...Ino, Chouji, Shikamaru, Neji they all learned their parents techniques, as well as sasuke learned his brothers techniques, and the way Kakashi was thought to be White Fang due to their similar techniques. So i think naruto is bound to learn that yellow flash thing.