wrong, attack speed stacks directly, 2 hyperstone gives you 110% increase in attack speed (1 hyperstone gives 55% ias)

and yes butterfly's evasion doesn't stack, but you're wrong too, having 2 butterflies makes no difference from having 1 if you're hit by a few enemies

and wrong again, if you have 2 dagon, you drop one, cast one, and you pick it back up, both dagons will have cooldown together

and lastly wrong 4, bash isn't the same as attack speed, it stacks with diminishing return(that's the reason you don't know), so a melee having 2 bashers doesn't have 30% chance, instead it's 1-(0.85x0.85)=27.75=28%