@Big_Boss
i saw the stand in the flashback, what im saying is that the bite could have just awakened her stand. her stand wasn't awakened back then, like with giorno as kid, when he subconsciously used his ability. yasuho just only later on as a young adult, discovered she had an ability.
no that wasn't an activation, nothing happened to them, if the stand was active, the ability would have took effect. tooru says if someone directly looks at his face or form, they never directly looked at him or his form in the stairway. when the ability took effect is the time rai, josuke and yasuho ran into tooru in the flesh, then tooru points out "akefu" and wonder of u activates which by the way, all three of them go under the effect of wonder of u. yasuho winds up almost getting hit by a car.
people always talk about inconsistency in stands but all it ever winds up being is people not paying more attention or thinking more about something...