It's a toss up between Darkseid and Wally West, as to drink with. I would just want to hear how awesome it is to rule Apokolips and maybe see a few people get the ol' Omega Beamed, and I'm sure he would relax after awhile and go crazy about his secret relationship with Granny Goodness,etc.
Wally West would be cool to talk to as well. Hearing stories about the Rogues, his womanizing days, and how cool it was to be Barry's sidekick.
As for a one night fling, I'm torn between Kendra Saunders, Hawk Girl, or Rita Farr, Elasti Girl from Doom patrol. Rita Farr would definitely need to wear her second outfit, the red and white one. I could just picture Power Girl being preoccupied lately thinking about her dead cousin and being the last survivor of the kryptonians from Earth 2. IF it was her during the Lighting Saga, when her and Hawkman hooked up, then I would think about it.