The issue is that Incite Emotion can kill. Once you kill the target, you can't then feed on it. If the target had been declared insane with lust or whatever as a takeout, then feeding would be possible. But he was killed.
Actually, you were the one to say that the victim was killed by incite emotion. The original wording was " took out an enemy with Incite Emotion".
My Opinion.
A taken out victim, as long as still alive, can be fed upon without trouble.
If the conflict is over, simply go with the dead from feeding result, and narrate it as the WCV Feeding on the helpless victim after the conflict as part of the take out.
If the Conflict is not yet over, and the character want's to feed and heal mid conflict but forgot to use his feeding power when taking out the target, then i'd let him feed on the taken out victim and heal, but I'd have that take up his next action.