poison is an orb affect it will only go to the main target of multishot type affects But.. we weird way to get around it is to give the multi shot an unnoticeable aura that only works for you and targets hit by the multishot and have the aura have poison affect on it.
It can be considered BUT the damage would be splashed (cleaving)
If a dummy unit is created for Picked unit, the dummy unit deals damage based on its own, not based on the Hero
A splashed damage is based on the Hero's current damage
adding poison splash to an attack, use Ramza's suggestion... and for a splash poison ability just use acid bomb directly, just create a new buff and make it look like poison and use it as the acid bomb's buff..