I'm leaning towards team 1 high difficulty.
I think Yamato's ground attacks and Sai's air attacks will give their team the victory. Temari is a huge threat to airborne Sai but if Yamato keeps her busy with constant mokuton attacks, Sai is relatively safe and can go on the offensive. Kankuro is relatively stationary and his attacks can't destroy mokuton so he isn't too much trouble for Yamato but Sasori's flamethrower can get an added boost from Temari. However, if Yamato's wood catches on fire, he can always extinguish them via suiton and can then go on to grow some more mokuton.
Poison gas carried off by wind is also deadly but Yamato can fuse with the surroundings while Sai can go airborne and spam paper tag explosions.
