Danzo low difficulty. Sure Kimimaro was strong in part 1 and was stronger than part 1 Gaara but Danzo is on the same level as MS Sasuke of all people. This is a mismatch IMO.
Here is a proper explanation on why Danzo wins. His wind blade will most definetely do damage against Kimimaro so you can't just say that Kimimaro will tank all of his attacks. Danzo has ten minutes of izanagi as well as sharingan precog. He had some impressive speed feats for an old man and matched Sasuke so I believe he would have an upperhand in a CQC fight. Danzo can ignore Kimimaro's bone offence/defence via izanagi and paralyse Kimimaro with a cursed seal. One he is paralysed, all Danzo needs to do is blast him with wind attacks until Kimimaro is dead.
Danzo also has a massive elephant that he can use to suck Kimimaro up or amplify his own wind attacks to slice Kimimaro just like Danzo sliced Sasuke's susanoo. I'm sure if Temari can hurt the 3rd Raikage who is much more durable than Kimimaro, Danzo can kill Kimimaro pretty easily.