About 1st example- that question is not about the very first chunin exam we see in anime but the Konoha-Suna joint exam, later on ,where first part was written test and examiner was Shikamaru http://naruto.wikia.com/wiki/Ch%C5%ABnin_Exams That question is missleading because there's no clear information about which exam it is.

About 2nd: Pain path's Tendo nature is lightning but Yahiko was using Water, Fire and Wind releases in anime (with water being his main nature it seems), not really Lightning.

Tendo n Yahiko both of them are the same right? make me confused.

Yahiko is definitely water, it was shown in manga and anime that he used water style.

Tendo (Deva Path), is just using Yahiko's body to perform jutsus that doesn't mean he's water style.

Ya they are just 1 body i just confused with the question. Yahiko from manga/anime or the game as tendo.

Just because Yahiko's body was used for Tendo does NOT make him tendo.

There were, for example, two Iterations of Chikushodo, the path is not tied to a specific body. Path of pain The six path of Rinnegan are their own entity, what form they take have no bearing on themselves.

I mean would you equate Kin Tsuchi with either the first or second hokage? Her body was used for the Edo Tensei of one of those, does not make them equivalent. Path of pain The six path of Rinnegan is similar, instead of reviving a specific soul, it is a possession of a specific entity. The fact that the outside appearance is mostly kept have no bearing on their identity or ability.

Edit: Six path of pain is an application of the six paths technique granted by rinnegan, due to Nagato's condition. However, the technique can be used by anyone with access to the base technique through possession of the eye. This includes, for example, Obito's use, thou in that case it was different since he couldn't use the path techniques due to the bodies being jinchurikis. Still, one of those body, thou never specified which, must be a "tendo" as well. As it stands, sasuke can have his own set if he so chooses. But generally speaking, one might not want to do so since 6-in-1 could be stronger. The only time it was used was due to need (Nagato) or alternate usage(Obito)