At the Drive-In with Metallica VS World Premiere of Justice League: The Flashpoint Paradox
They aren't a conflict from a time standpoint unless you count getting from Hall H to Ballroom 20 and the line to get into the World Premiere :-\
Keep in mind that they are re-showing the Justice League at 9:30pm. There won't be a panel, but you would get to see the movie. That is probably what we will do.