Re: Kisame and Diedera Vs Kakazu and Sasori
While thinking to create it Totally agree with scenario 1.
Having Kisame as a Deidara's teammate imo is absolutely haxed. Supplying chakra to Deidara means, for example, Deidara can spam C4 as much as needed. Can even send off a shadow clone to prepare C3 within minutes, while real Deidara fight on, and not worry about chakra levels. Kisame can go underground and place C2 mines for Deidara or Deidara's shadow clone can do it. Very few can actually take on Kisame and Deidara.
Sasori and Kisame on the other hand doesn't help Sasori that much.
First of all, Sasori's stamina is already very high and that is on top of the fact that puppet techniques doesn't consume a lot of chakra. Iron Sand Techniques, however, takes up substantial amount of chakra to execute. Giving Sasori more chakra would only mean longer and more ferocious usage of Iron Sand, which is nowhere as lethal as bigger and more gigantic explosions.
Kisame and Deidara
Kakuzu and Deidara (assuming Iron Sand doesn't get through Domu, in which case Kakuzu trashes Sasori mid difficulty and helps Deidara tip the balance against Kisame)