Even though KA won't work on Sasori couldn't that eye be used for one Izanagi? That could allow Danzo time to remove the seal on his arm and use Izanagi ten more times. That could make the battle last longer and allow Danzo to take out the 100 puppets with his other jutsu and summon.
That being said, Sasori still takes both scenarios because he's just too much for Danzo. Sasori will outlast him or poison him.
Danzo wins low to medium difficulty when Sasori is restrained to Hiruko.
Sasori will be winning with medium to high difficulty if he's not confined to Hiruko at the start. His poison, the large use of puppets and Iron Sand are more than enough to cause Danzo significant harm. The only way I see Danzo winning is if he is capable of using this last technique and use Izanagi to survive after it [
Sasori couldn't even kill Sakura nor an old girl and was the first Edo to lose. In the fight between Danzo and Sasuke, it would have been a tie had Karin not healed Sasuke.