1-5.. completly ansewered...
6...Do I take damage from Mage Bane if I Steal Enchantment and attach it to his/her mage?
I think you are talking about, do you take damage from using your opponents enchantment...
You would take damage from casting steal enchantment, but you will not take damage from attaching the targeted enchantment on a new target...
Or so i think... since you are not casting the enchantment, you are just moving it, as the card reads, and magebane specifically reads, when u cast and resolve a spell...