Also, you're correct, the evidence of the one being used on danzo , is small indeed, its more possible it could have been a normal genjutsu , But the bee one, he displayed all signs similar too itachis , adamant on that 1
Kakashi said ITACHI's genjutsu has no cancellation.. he said it twice, itachi's tsukyomi starts and finishes in 1 second, Instant.. which means there is 0 time for anyone to possibly cancel it.... As danzo said itachi can manipulate your perception of time at his whim, thus can make that 1 second feel like however amount of days he wishes.... in kakashi's case he gave him 3 days, which he spared his life with (had no intent to kill )
Sasukes tsukyomi is like any other genjutsu, where it has a lingering effect, bee was there on the floor paralyzed for a bit before hachibi disrupted his flow, you see here that sasuke's tsukyomi allows time for cancellations