A can beat Hidan,Zetsu and Kisame but that's about it.
Really? Kisame Is not the fastest guy in Akatsuki, but Samehada absorbs 6-tails worth of chakra (refering to the fight against Killerbee). A uses chakra for the lightning armor and eventhough he is insanely fast, Samehada might be able to absorb the chakra like it did to the 8-tail cloak. A might find out about before it is to late and use a lariat wich mich create the same scenario as Killerbee faced (because they ar equal in strength when it comes too lariat and Killerbee was in 8-tails cloak mode)
Here is how I think the fight will go (I am placing this fight at the same place were Killerbee and Kisame fought): A attacks Kisame head on and Samehada absorbs the chakra A uses for his lightning armor. It goes like that for three rounds (lariats and other attacks) until he realizes that Samehada is absorbing chakra (Kisame might say it because he likes to brag about it). A pulls his body flicker technique to max (like he did when he fhougt Sasuke's mangekyou sharingan), by doing that he can land a lariat and Kisame protects himself with Samehada. Kisame is wounded and Samehada heals him. Kisame use shark dance technique, sync with Samehada and A will struggle because Kisame has gotten about equaly fast, but the thing that will end the battle: Raikage A fights closeranga and as long as he touches Kisame he will lose his chakra. A will be at the verge of death.
Raikage A is extremley fast, very strong and the fight will take a while, but the battle will be almost just like the match between Kisame and killerbee (I think).
Zetsu are to persons so the white one can plant the spores and the black activates them. I remember that the spores were easy to beat for the kages, but only one person against many spores does not look good. I think the raikage would lose a lot of chakra, but he is most likely victorious.