Kisame was just killing time with Team Snake until the duel was over. Itachi's dead and Kisame is probably on his way to the closest waypoint or the rain country to get a new partner.
As for Saske, this is bullshit, the last thing Itachi intended. He wanted to keep the villiage in one peice, and did this, that, and the next thing to make sure it did.
Now Saske is going to ... destroy the villiage anyways! Brilliant! His true enemy is the Zabi family! I mean... Fuck I've seen this too many times to remember the name.