PoE TumbleweedBulky6099 builds

I am planning for next league a meme build. Yes next league i like to be prepared :). The idea is to use on hit + slows + poison. I mostly have questions relating to slows on enemies. 1 Does movement speed slow also affect things such as casting speed? Just movement speed or also casts that include movement? 2 how do sources of slow stack? Lets say Maim + chill is it added together and subtracted or are each subtractated after eachother? As for the build i am not that far with it, but if you want to have a laugh or have any suggestions let me know. Core elements: Life/mana o