[Etaoin Shrdlu]

Since no-one has gone after original question 3):
If the sieging nation casts, it hits the defenders. If the defenders cast, it hits the siege force. Not sure what happens if a third nation casts-- anyone want to test that?
And on 4): Winter Bringer (casts Falling Frost for free, yay) probably shouldn't be unique. Be sure to load MR items on holder of Stone Sword or Sword of Many Colors. Carcator's +2 research is lost since you likely have all research sewn up within the next 15 or so turns, a real what's the point? situation.