Itachi was programed to react to enemy jutsu, meaning dodge attacks , etc....
Could he or kabuto break ka?
No
He didn't call it the Ultimate Genjutsu for nothing.. Tobi and kabuto weren't after it for nothing....Shishui didn't make it look he destroyed the eyes so people wouldn't fight for his body for nothing..... Kishi didn't put a 10 year limit then destroy both eyes from naruto world and not revive shishui for nothing...
You severely underestimate its power..
Yes danzo can win anybattle.... If you didnt realize , Plot no jutsu made sure he used ka before fighting with sasuke...