New Redemption Grab Bag now includes an assortment of 500 cards from five (5) different expansion sets. Available at Cactus website.
Copy is CBI.
I believe that since the 'imitate' soul gained the ability of the 'humble' soul during upkeep, to negate the soul as 'imitate' that would have to be done during the same upkeep, after that you would only be able to negate the soul it has become. (If the soul it became was negatable)
but it shouldn't matter if the copy is CBI, because it copied something that is CBN, and once a CBN ability is activated, there is no way to negate it
is there any other evidence of abilities just ceasing to exist?
there is evidence of CBN abilities staying around after they have been indirectly negated