For Interrupt/Negates, You must have either Insitative or if your last Character is being taken out of battle by a card effect that is not CBI/CBN. At that point you may Interrupt the card removing you from battle. If neither of the requirements are met, then you cannot 'Interrupt'.
But for Interrupt cards like a Curse, ( or Negating one) like if you played Abraham's Desendent, it stops its effect alltogether until the effect is completed. With Abe's Kids, that would be after its added to Hand, with in effect negates it.
Hope this helps
