So I ran into this during last week's post-skullbats casuals, and I tested / verified it again just now. There doesn't appear to be a way to go into button configuration when you are doing lobby play.... I tried hitting the "Start" button in the character select screen, before picking 1,2,3 characters. Usually, this prompts the button configuration menu, but during lobby play ONLY, this doesn't seem to happen. It seemingly works in every other character select screen I've been in though. Has anyone else run into this at all?