The rinegan said to be the best Doujutsu, because of the Sage of six's path capabilities. Nagato's rinnegan aint nothing compared to the So6P. The So6p had other abilites with his Rinnegan that Nagato dosent have.
And the reason is because Nagato is only 1 Path. Nagato is the 3rd path.
The Sage of six paths is ALL Paths. So yes the Rinnegan is the best Doujutsu since it had the Complete version if Izanagi, and Genjutsu to control the ten tailed, and other capabilites. But since Nagato isnt the SO6P he dosent have all of those techniques, because he's only 1 PAth. RInnegan IS the best DOujutsu. But nagato's version isnt, since he's only 1 path, and only has a certain extent of the so6p abilites.
Raikage was the Fastet ninja, alive. Naruto "WAS" slower than him. But he "Became faster than him with Kyuubi mode. SO before, Raikage WAS the fastest ninja alive. (since minato dead)
but that jinchuriki stuff you said, Yes they can be affected by genjutsu, its just that a 'perfect bijuu' can cancel the genjutsu with its chakra, if its a Genjutsu thats able to be released in such a method