Lily explained the transformation - take one Avada Kedavra, one anti-AK charm (experimental), mix with a combination of magical and mundane flora and one brainy witch and age for several years. Harley Quinn, Darkseid, and the Pie - surprisingly, the pie actually made SENSE (though it sounds like something out of slapstick); Darkseid's major weapon is his Omega Beams - like Kryptonian heat vision, it's fired from - his eyes. Pie-to-the-face (of Darkseid - or any Kryptonian) is like plugging a firearm with the side effect of causing blindness. The transformed Lily apparently hid in Gotham (which ALSO makes sense - two different ways - as Harley knows exactly who she really is, AND hiding amidst the rabble and under the radar makes sense when you're supposed to be quite dead). Harley and Sirius - COnsidering that Sirius is quite alive, that ALSO makes sense (in a rather quirky way) - reformed crook is now dating medically-retired policeman (Sirius was an Auror until his wrongful arrest and imprisonment without trial - the side-effects of Club Azkaban meant he couldn't go back to his old job, even if he wanted to). Meanwhile, Superman is going to find himself in a quandary - facing longtime on-and-off love-interest Lois Lane - with his relations not only BOTH married (to the same human wizard), he's running out of excuses for NOT marrying Lois. As even Zod would tell him, "Kal-El - desist thy needless stalling!"