Arcane shield, and pet question

Hi AL :) I'm taking advantage of double xp to try and cap my mage. It's at lvl 42 now, and I have some questions I can't find the answers for (I have tried, lol).

Arcane shield: do the first and third updates of increasing damage reduction 15% stack? So you'd get 70% dmg reduction with charged Shield (40+15+15)?

Does this dmg reduction stack with Nekro and Blinky AAs? (I think not, but just checking).

Also, do you think Toor is good for mage? I've got Mari on my rogue which I love, but I'd like to try clocking/stunning mobs and using Toor's AA on them. Sounds like fun.

Arcane shield does not reduce 70% dmg it reduces 55%. The first update is saying that it can take 15% more damage the third update says it reduces 15% more dmg