Iki is what Sköll was like in the beginning, before living for eons slowly changed him.Being reborn in effect "reseted" him.
Muninn is not permanently dead.When Hati is ranting at Sköll, he said that Sköll and Askr went to the "only place Askr could be harmed" which was the netherworld. This implies one of two things. One, that Askr and Askr alone was invincible everywhere but there. Or two, that all White and Black Spirits in general cannot be killed permanently except for in the netherworld. My bet is on the later. Muninn did not die in the netherworld, so he will be reborn if the world of Off-White lasts long enough.
We will slowly watch the cast get more and more immoral as time goes on.The comic pretty much states that when a White or Dark Spirit dies, the aspect of that spirit along with it's species and brother species dies with it eventually. Askr was killed permanently, and she was the guardian of good, so it would be logical to assume that eventually this comic is slowly going to turn into Evil Versus Evil. Maybe the cast will wrestle with the darkness inside them, trying to desperately hold on to their morality before giving into the darkness, and becoming fully evil.
Raigho can see into the spirit world.