I'm wondering

Does the poisin element staff affect DoT dmg or jsut activation dmg?

Just the activation
DoT are set formulas.
They don't change---- Right Bigfoot?

When they add the % bonusses I think it will only work on the main attack, not on the effects after that. The poison one would probably have the best effect on Paralyze because the base damage from Poison Mist isnt what one would call great..

So Im guessing
Poisin Weapon>Fire Weapon?

No, Fire weapon > Poison weapon. xd Unless you're using paralyze.

Fire/Ice wands are best for training. Poison/Lightning wands are best for bossing.