Alot of people are just analysing kakashi's and neji's abilities and disregarding hidans and deidora, therefore their decision makes no sense.
Anyway ill go with hidan and deidora. Due to hidans abilities he would work extremely well with deidora. Deidora can bomb raid kakashi and neji whilst hidan attacks them at the same time, thus taking advantage of his immortality.
Not to forget without info on hidan, he can kill anybody. Infact due to his abilities he relishes taijutsu and this is the only form of ninja art that neji uses. Against hidan the best thing to do is to stay away from him. Once your blood is drawn, its game over and tbh i can see him getting blood from neji.
Now kakashi has already proven that he can use kumai quiet effectively and infact used it on deidora, but he isnt skilled enough at it to teleport his whole body. Anyway kakashi like sasuke can counter his bombs due to his chakra affiliation and i do think he would notice that, but at the same time i doubt he would come up with different senarios like sasuke did.
If worse come to worse, deidora can blow himself up and take neji and kakashi with him to the after life, but hidan will survive, because he will be the last man standing, team deidora and hidan win