A couple questions about shields

First, about stacking shields.

Say a target receives shield, Eye of the Storm, and his own Soul Furnace, before getting ticked down by a Swain.

Which shield would be consumed first?

It doesn't so much matter for the health itself, but the bonuses granted by certain shields. Say, for the sake of argument, that all these shields are shielding for an equal amount. If Sion was to take enough damage to break one of them, which buff is lost first? The mere shielding from locket, the AD from Janna, or the nuke potential from Soul furnace?

The next question isn't so much about the mechanic of shields, but about .

If one was to purchase a dorans shield, would they take reduced damage from the basic attacks of champion pets? If so, this should be a considered starting item for any melee playing against a , as it would mitigate 2/3 of his turrets cannon damage at level 1 (premitigation).