Kisame wins with Samehada, close range power houses like the raikage who use chakra shrouds are shark food for Kisame and samehada, literally.
Any damge A inflicts will be healed by samehada and every hit will mean A loses six tails worth of chakra, A fights like B, accept instead of Bijuu cloaks he uses a lightning cloak, he also has Bijuu level chakra reserves as karin noted, he is just like a jinchuuriki, which are Kisame's specialty, I don't see A winning this, its a bad match up.
Kisame without samehada would definately lose though, he stands no chance then.