I myself don't want those answers; a good story should leave some things to imagination.
But here are 3 silly answers and 3 non/less silly:
1) Red Shirt Man, from the 23rd century Starfleet.
2) Acme, same place Wiley Coyote gets his supplies.
3) His debutante gown.
4) Serious answer for once: Levitz left it vague so as not to be tied to a single version of Darkseid's 'last battle' (since there's always another one every few years). Smart move on his part, leaving mystery rather than getting tied to a carpet likely to be pulled out from under him.
5) he probably cheated. and the good guys didn't.
6) it didn't fit 'continuity,' but it was a neat twist.