I believe KA could work on Pain, he uses
Chakra Receivers to control their movements, they all have the Rinnegan, meaning they all share the same vision, including Nagato himself.
"By using chakra receivers on corpses, Nagato can manipulate the bodies as though they were his own."
"The Six Paths of Pain were all reanimated corpses that Nagato gave the Rinnegan to through some unknown means. By doing so, Nagato could see each individual body's field of vision, coordinating the bodies with extremely precise planning."
If Nagato see's what all the Paths see, then he can certainly be trapped in a Genjutsu, and for those who argue that the Paths simply don't have to make eye contact, KA:
"This technique seemingly did not require direct eye contact, as demonstrated when Danzō manipulated Mifune's thoughts without exposing his Sharingan."
Also, Danzo still has Izanagi and cant die for 10 minutes. So for 10 minutes he's:
A. Indestructible
B. Able to catch Pain by surprise consistently for 10 minutes straight
C. Can go for suicide attacks if needed to defeat the Paths 1 at a time and reappear after without a scratch