It seems to me that the so-called Joker would have had to move pretty darn quick during the action in DK@ number 2. Not only was he able to kill both the Guardian and the Creeper within minutes, he was also able to change his costume. And he didn’t seem to care at all that he went up in flames with J’onn.
My idea: That we are seeing a few individuals in some type of army of Joker clones/androids, each targeted by Lex and Brainiac for a specific second-tier hero.
By the end of the week I am sure I will have to eat these words…