I think that this version of Song of Earendil is much too strong. It allows you to skip questing for 1 resource and 0 cards. Maybe "after you raise your threat from encounter card effect"? Or doomed keyword? There is a similar card right now (it's called Free Choice I think), it's cost 0 but doesn't draw you a card

Ok, I take your point. What about this:

Song of Earendil - Attach to a Spirit hero. Response: After Song of Eärendil enters play, draw 1 card. Response: After you raise your threat outside of the quest phase, discard Song of Earendil to reduce your threat by the same amount.

Sounds interesting. It can always be used to cancel one point of threat at the end of the round, but if comboed it can easily go up to 3-4 threat. It's a shame that Hill troll and Ungoliant Spawn (her shadow effect) are not in this cycle, but as this card redraws itself it should always be at least playable.