I have not tested it yet, but it seems realistic. Same for ghost: if one enemy has ghost and you remove it, he dies directly. So this seems to be an intended thing.
For the time bomb: I am also interested if there are more toons to do that, as it will be the next challenge to do for me. I neither have Iron Eddie nor purple Lilith (wasn't her power move something with time bomb also?). So is there only blue Trickster left?