When you are resolving the Westeros Cards, do you reveal then resolve I, , then II, then III,

or do you reveal I, II, and III at the same time, and then resolve I, then II, then III?

thanks

You reveal I+II+III, then resolve I+II+III.

This means you know if there's a Wildling Attack this turn when you choose to spend power on Clash of Kings (for example).

After resolving the Westeros cards, do you discard them or just place them back at the bottom of their designated decks?

leave them face up on a continually increasing discard stack so you can revisit the wildling threat level (if needed).

above the stacks or below them will suffice.