much of the filler contradicts the story. the filler character "sora" was supposedly imbued with the kyuubi's yang chakra becausethe 4th only sealed the yin chakra inside Naruto. This was wrong, because Minato sealed the yang chakra with the reaper death seal, while sealing the yin chakra inside naurto.
Somebody quoted in another thread that the 4th mizukage, released his bijuu in order to commit suicide after somebody was able to weaken the genjutsu controling him, however nobody in the mist village was apparently able to break it entirely. Rather this is true or not I haven't found in the manga.[/QUOT
As far as I know, someone in d Akatsuki (maybe Madara / can't remember) told that the 3 tails beast dont have a host.